diff --git a/scss/_badge.scss b/scss/_badge.scss
index 2082f058ec..42c5d08d74 100644
--- a/scss/_badge.scss
+++ b/scss/_badge.scss
@@ -16,7 +16,7 @@
   @include transition($badge-transition);
 
   @at-root a#{&} {
-    @include hover-focus {
+    @include hover-focus() {
       text-decoration: none;
     }
   }
diff --git a/scss/_button-group.scss b/scss/_button-group.scss
index d7220029ad..da02d7931b 100644
--- a/scss/_button-group.scss
+++ b/scss/_button-group.scss
@@ -13,7 +13,7 @@
 
     // Bring the hover, focused, and "active" buttons to the front to overlay
     // the borders properly
-    @include hover {
+    @include hover() {
       z-index: 1;
     }
     &:focus,
diff --git a/scss/_buttons.scss b/scss/_buttons.scss
index 2a7d94ad22..0740e05848 100644
--- a/scss/_buttons.scss
+++ b/scss/_buttons.scss
@@ -17,7 +17,7 @@
   @include button-size($btn-padding-y, $btn-padding-x, $btn-font-size, $btn-line-height, $btn-border-radius);
   @include transition($btn-transition);
 
-  @include hover {
+  @include hover() {
     color: $body-color;
     text-decoration: none;
   }
@@ -79,7 +79,7 @@ fieldset:disabled a.btn {
   color: $link-color;
   text-decoration: $link-decoration;
 
-  @include hover {
+  @include hover() {
     color: $link-hover-color;
     text-decoration: $link-hover-decoration;
   }
diff --git a/scss/_card.scss b/scss/_card.scss
index 52df99a394..fdbe95f404 100644
--- a/scss/_card.scss
+++ b/scss/_card.scss
@@ -56,7 +56,7 @@
 }
 
 .card-link {
-  @include hover {
+  @include hover() {
     text-decoration: none;
   }
 
diff --git a/scss/_carousel.scss b/scss/_carousel.scss
index 3ff2d37be8..76ab23fedd 100644
--- a/scss/_carousel.scss
+++ b/scss/_carousel.scss
@@ -101,7 +101,7 @@
   @include transition($carousel-control-transition);
 
   // Hover/focus state
-  @include hover-focus {
+  @include hover-focus() {
     color: $carousel-control-color;
     text-decoration: none;
     outline: 0;
diff --git a/scss/_close.scss b/scss/_close.scss
index 5cc96f573e..071aebe80f 100644
--- a/scss/_close.scss
+++ b/scss/_close.scss
@@ -8,13 +8,13 @@
   opacity: .5;
 
   // Override <a>'s hover style
-  @include hover {
+  @include hover() {
     color: $close-color;
     text-decoration: none;
   }
 
   &:not(:disabled):not(.disabled) {
-    @include hover-focus {
+    @include hover-focus() {
       opacity: .75;
     }
   }
diff --git a/scss/_dropdown.scss b/scss/_dropdown.scss
index c657c5d103..6c688f6ace 100644
--- a/scss/_dropdown.scss
+++ b/scss/_dropdown.scss
@@ -144,7 +144,7 @@
     }
   }
 
-  @include hover-focus {
+  @include hover-focus() {
     color: $dropdown-link-hover-color;
     text-decoration: none;
     @include gradient-bg($dropdown-link-hover-bg);
diff --git a/scss/_list-group.scss b/scss/_list-group.scss
index bc27a71b5b..468c2e31ac 100644
--- a/scss/_list-group.scss
+++ b/scss/_list-group.scss
@@ -23,7 +23,7 @@
   text-align: inherit; // For `<button>`s (anchors inherit)
 
   // Hover state
-  @include hover-focus {
+  @include hover-focus() {
     z-index: 1; // Place hover/focus items above their siblings for proper border styling
     color: $list-group-action-hover-color;
     text-decoration: none;
diff --git a/scss/_nav.scss b/scss/_nav.scss
index 2085d06f67..667d682721 100644
--- a/scss/_nav.scss
+++ b/scss/_nav.scss
@@ -15,7 +15,7 @@
   display: block;
   padding: $nav-link-padding-y $nav-link-padding-x;
 
-  @include hover-focus {
+  @include hover-focus() {
     text-decoration: none;
   }
 
@@ -42,7 +42,7 @@
     border: $nav-tabs-border-width solid transparent;
     @include border-top-radius($nav-tabs-border-radius);
 
-    @include hover-focus {
+    @include hover-focus() {
       border-color: $nav-tabs-link-hover-border-color;
     }
 
diff --git a/scss/_navbar.scss b/scss/_navbar.scss
index 430858ccdd..d678017255 100644
--- a/scss/_navbar.scss
+++ b/scss/_navbar.scss
@@ -48,7 +48,7 @@
   line-height: inherit;
   white-space: nowrap;
 
-  @include hover-focus {
+  @include hover-focus() {
     text-decoration: none;
   }
 }
@@ -113,7 +113,7 @@
   border: $border-width solid transparent; // remove default button style
   @include border-radius($navbar-toggler-border-radius);
 
-  @include hover-focus {
+  @include hover-focus() {
     text-decoration: none;
   }
 }
@@ -194,7 +194,7 @@
   .navbar-brand {
     color: $navbar-light-brand-color;
 
-    @include hover-focus {
+    @include hover-focus() {
       color: $navbar-light-brand-hover-color;
     }
   }
@@ -203,7 +203,7 @@
     .nav-link {
       color: $navbar-light-color;
 
-      @include hover-focus {
+      @include hover-focus() {
         color: $navbar-light-hover-color;
       }
 
@@ -234,7 +234,7 @@
     a {
       color: $navbar-light-active-color;
 
-      @include hover-focus {
+      @include hover-focus() {
         color: $navbar-light-active-color;
       }
     }
@@ -246,7 +246,7 @@
   .navbar-brand {
     color: $navbar-dark-brand-color;
 
-    @include hover-focus {
+    @include hover-focus() {
       color: $navbar-dark-brand-hover-color;
     }
   }
@@ -255,7 +255,7 @@
     .nav-link {
       color: $navbar-dark-color;
 
-      @include hover-focus {
+      @include hover-focus() {
         color: $navbar-dark-hover-color;
       }
 
@@ -286,7 +286,7 @@
     a {
       color: $navbar-dark-active-color;
 
-      @include hover-focus {
+      @include hover-focus() {
         color: $navbar-dark-active-color;
       }
     }
diff --git a/scss/_reboot.scss b/scss/_reboot.scss
index 4955f7fe8f..bdb53f346a 100644
--- a/scss/_reboot.scss
+++ b/scss/_reboot.scss
@@ -188,7 +188,7 @@ a {
   text-decoration: $link-decoration;
   background-color: transparent; // Remove the gray background on active links in IE 10.
 
-  @include hover {
+  @include hover() {
     color: $link-hover-color;
     text-decoration: $link-hover-decoration;
   }
@@ -204,7 +204,7 @@ a:not([href]):not([tabindex]) {
   color: inherit;
   text-decoration: none;
 
-  @include hover-focus {
+  @include hover-focus() {
     color: inherit;
     text-decoration: none;
   }
diff --git a/scss/_tables.scss b/scss/_tables.scss
index 11259153f2..5fd77a4eb0 100644
--- a/scss/_tables.scss
+++ b/scss/_tables.scss
@@ -84,7 +84,7 @@
 
 .table-hover {
   tbody tr {
-    @include hover {
+    @include hover() {
       color: $table-hover-color;
       background-color: $table-hover-bg;
     }
@@ -149,7 +149,7 @@
 
   &.table-hover {
     tbody tr {
-      @include hover {
+      @include hover() {
         color: $table-dark-hover-color;
         background-color: $table-dark-hover-bg;
       }
diff --git a/scss/mixins/_background-variant.scss b/scss/mixins/_background-variant.scss
index 89b8849b1c..c209d7ca50 100644
--- a/scss/mixins/_background-variant.scss
+++ b/scss/mixins/_background-variant.scss
@@ -8,7 +8,7 @@
   }
   a#{$parent},
   button#{$parent} {
-    @include hover-focus {
+    @include hover-focus() {
       background-color: darken($color, 10%) !important;
     }
   }
diff --git a/scss/mixins/_badge.scss b/scss/mixins/_badge.scss
index 64b29cb579..f1c499141a 100644
--- a/scss/mixins/_badge.scss
+++ b/scss/mixins/_badge.scss
@@ -3,7 +3,7 @@
   background-color: $bg;
 
   @at-root a#{&} {
-    @include hover-focus {
+    @include hover-focus() {
       color: color-yiq($bg);
       background-color: darken($bg, 10%);
     }
diff --git a/scss/mixins/_buttons.scss b/scss/mixins/_buttons.scss
index 874f552d0c..c82c4d6d09 100644
--- a/scss/mixins/_buttons.scss
+++ b/scss/mixins/_buttons.scss
@@ -9,7 +9,7 @@
   border-color: $border;
   @include box-shadow($btn-box-shadow);
 
-  @include hover {
+  @include hover() {
     color: color-yiq($hover-background);
     @include gradient-bg($hover-background);
     border-color: $hover-border;
@@ -65,7 +65,7 @@
   color: $color;
   border-color: $color;
 
-  @include hover {
+  @include hover() {
     color: $color-hover;
     background-color: $active-background;
     border-color: $active-border;
diff --git a/scss/mixins/_caret.scss b/scss/mixins/_caret.scss
index 07d72280ce..27466495b2 100644
--- a/scss/mixins/_caret.scss
+++ b/scss/mixins/_caret.scss
@@ -1,25 +1,25 @@
-@mixin caret-down {
+@mixin caret-down() {
   border-top: $caret-width solid;
   border-right: $caret-width solid transparent;
   border-bottom: 0;
   border-left: $caret-width solid transparent;
 }
 
-@mixin caret-up {
+@mixin caret-up() {
   border-top: 0;
   border-right: $caret-width solid transparent;
   border-bottom: $caret-width solid;
   border-left: $caret-width solid transparent;
 }
 
-@mixin caret-right {
+@mixin caret-right() {
   border-top: $caret-width solid transparent;
   border-right: 0;
   border-bottom: $caret-width solid transparent;
   border-left: $caret-width solid;
 }
 
-@mixin caret-left {
+@mixin caret-left() {
   border-top: $caret-width solid transparent;
   border-right: $caret-width solid;
   border-bottom: $caret-width solid transparent;
diff --git a/scss/mixins/_float.scss b/scss/mixins/_float.scss
index adff88e790..6b376a2580 100644
--- a/scss/mixins/_float.scss
+++ b/scss/mixins/_float.scss
@@ -1,14 +1,14 @@
 // stylelint-disable declaration-no-important
 
-@mixin float-left {
+@mixin float-left() {
   float: left !important;
   @include deprecate("The `float-left` mixin", "v4.3.0", "v5");
 }
-@mixin float-right {
+@mixin float-right() {
   float: right !important;
   @include deprecate("The `float-right` mixin", "v4.3.0", "v5");
 }
-@mixin float-none {
+@mixin float-none() {
   float: none !important;
   @include deprecate("The `float-none` mixin", "v4.3.0", "v5");
 }
diff --git a/scss/mixins/_hover.scss b/scss/mixins/_hover.scss
index 192f847e17..409f8244e1 100644
--- a/scss/mixins/_hover.scss
+++ b/scss/mixins/_hover.scss
@@ -9,18 +9,18 @@
 //
 // Issue: https://github.com/twbs/bootstrap/issues/25195
 
-@mixin hover {
+@mixin hover() {
   &:hover { @content; }
 }
 
-@mixin hover-focus {
+@mixin hover-focus() {
   &:hover,
   &:focus {
     @content;
   }
 }
 
-@mixin plain-hover-focus {
+@mixin plain-hover-focus() {
   &,
   &:hover,
   &:focus {
@@ -28,7 +28,7 @@
   }
 }
 
-@mixin hover-focus-active {
+@mixin hover-focus-active() {
   &:hover,
   &:focus,
   &:active {
diff --git a/scss/mixins/_image.scss b/scss/mixins/_image.scss
index a76a6082ba..c971e038be 100644
--- a/scss/mixins/_image.scss
+++ b/scss/mixins/_image.scss
@@ -7,7 +7,7 @@
 //
 // Keep images from scaling beyond the width of their parents.
 
-@mixin img-fluid {
+@mixin img-fluid() {
   // Part 1: Set a maximum relative to the parent
   max-width: 100%;
   // Part 2: Override the height to auto, otherwise images will be stretched
diff --git a/scss/mixins/_list-group.scss b/scss/mixins/_list-group.scss
index cd47a4e9fa..0da3531561 100644
--- a/scss/mixins/_list-group.scss
+++ b/scss/mixins/_list-group.scss
@@ -6,7 +6,7 @@
     background-color: $background;
 
     &.list-group-item-action {
-      @include hover-focus {
+      @include hover-focus() {
         color: $color;
         background-color: darken($background, 5%);
       }
diff --git a/scss/mixins/_lists.scss b/scss/mixins/_lists.scss
index 2518562669..251cb07331 100644
--- a/scss/mixins/_lists.scss
+++ b/scss/mixins/_lists.scss
@@ -1,7 +1,7 @@
 // Lists
 
 // Unstyled keeps list items block level, just removes default browser padding and list-style
-@mixin list-unstyled {
+@mixin list-unstyled() {
   padding-left: 0;
   list-style: none;
 }
diff --git a/scss/mixins/_reset-text.scss b/scss/mixins/_reset-text.scss
index bfa9f6e9ad..15b4407a0a 100644
--- a/scss/mixins/_reset-text.scss
+++ b/scss/mixins/_reset-text.scss
@@ -1,4 +1,4 @@
-@mixin reset-text {
+@mixin reset-text() {
   font-family: $font-family-base;
   // We deliberately do NOT reset font-size or word-wrap.
   font-style: normal;
diff --git a/scss/mixins/_screen-reader.scss b/scss/mixins/_screen-reader.scss
index e2de4cba4d..21230390eb 100644
--- a/scss/mixins/_screen-reader.scss
+++ b/scss/mixins/_screen-reader.scss
@@ -3,7 +3,7 @@
 // See: https://a11yproject.com/posts/how-to-hide-content/
 // See: https://hugogiraudel.com/2016/10/13/css-hide-and-seek/
 
-@mixin sr-only {
+@mixin sr-only() {
   position: absolute;
   width: 1px;
   height: 1px;
@@ -21,7 +21,7 @@
 //
 // Credit: HTML5 Boilerplate
 
-@mixin sr-only-focusable {
+@mixin sr-only-focusable() {
   &:active,
   &:focus {
     position: static;
diff --git a/scss/mixins/_table-row.scss b/scss/mixins/_table-row.scss
index f8d61869a4..1ccde6b6c5 100644
--- a/scss/mixins/_table-row.scss
+++ b/scss/mixins/_table-row.scss
@@ -26,7 +26,7 @@
     $hover-background: darken($background, 5%);
 
     .table-#{$state} {
-      @include hover {
+      @include hover() {
         background-color: $hover-background;
 
         > td,
diff --git a/scss/mixins/_text-emphasis.scss b/scss/mixins/_text-emphasis.scss
index 155d6ca8cf..1739e2d08d 100644
--- a/scss/mixins/_text-emphasis.scss
+++ b/scss/mixins/_text-emphasis.scss
@@ -8,7 +8,7 @@
   }
   @if $emphasized-link-hover-darken-percentage != 0 {
     a#{$parent} {
-      @include hover-focus {
+      @include hover-focus() {
         color: darken($color, $emphasized-link-hover-darken-percentage) !important;
       }
     }
diff --git a/scss/utilities/_text.scss b/scss/utilities/_text.scss
index 589e5687a8..ce1565032b 100644
--- a/scss/utilities/_text.scss
+++ b/scss/utilities/_text.scss
@@ -11,7 +11,7 @@
 .text-justify  { text-align: justify !important; }
 .text-wrap     { white-space: normal !important; }
 .text-nowrap   { white-space: nowrap !important; }
-.text-truncate { @include text-truncate; }
+.text-truncate { @include text-truncate(); }
 
 // Responsive alignment
 
diff --git a/site/docs/4.3/assets/scss/_component-examples.scss b/site/docs/4.3/assets/scss/_component-examples.scss
index 62ebf6953b..2524f68b23 100644
--- a/site/docs/4.3/assets/scss/_component-examples.scss
+++ b/site/docs/4.3/assets/scss/_component-examples.scss
@@ -87,7 +87,7 @@
   height: 3rem;
   margin-bottom: .5rem;
   background-color: lighten($blue, 50%);
-  @include border-radius;
+  @include border-radius();
 }
 
 .bd-example-container-sidebar {
@@ -95,14 +95,14 @@
   width: 4rem;
   height: 8rem;
   background-color: lighten($blue, 25%);
-  @include border-radius;
+  @include border-radius();
 }
 
 .bd-example-container-body {
   height: 8rem;
   margin-right: 4.5rem;
   background-color: lighten($bd-purple, 25%);
-  @include border-radius;
+  @include border-radius();
 }
 
 .bd-example-container-fluid {
diff --git a/site/docs/4.3/assets/scss/_skippy.scss b/site/docs/4.3/assets/scss/_skippy.scss
index db971d114c..bd2aadb82a 100644
--- a/site/docs/4.3/assets/scss/_skippy.scss
+++ b/site/docs/4.3/assets/scss/_skippy.scss
@@ -6,7 +6,7 @@
   background-color: $bd-purple;
   outline: 0;
 
-  @include hover {
+  @include hover() {
     color: $white;
   }
 }