diff --git a/ansi/sgr.go b/ansi/sgr.go
index 7c019117..4d6c5768 100644
--- a/ansi/sgr.go
+++ b/ansi/sgr.go
@@ -46,7 +46,6 @@ var attrStrings = map[int]string{
 	ReverseAttr:                      "7",
 	ConcealAttr:                      "8",
 	StrikethroughAttr:                "9",
-	NoBoldAttr:                       "21",
 	NormalIntensityAttr:              "22",
 	NoItalicAttr:                     "23",
 	NoUnderlineAttr:                  "24",
diff --git a/ansi/style.go b/ansi/style.go
index 46ddcaa9..92c83e58 100644
--- a/ansi/style.go
+++ b/ansi/style.go
@@ -127,11 +127,6 @@ func (s Style) Strikethrough() Style {
 	return append(s, strikethroughAttr)
 }
 
-// NoBold appends the no bold style attribute to the style.
-func (s Style) NoBold() Style {
-	return append(s, noBoldAttr)
-}
-
 // NormalIntensity appends the normal intensity style attribute to the style.
 func (s Style) NormalIntensity() Style {
 	return append(s, normalIntensityAttr)
@@ -236,7 +231,6 @@ const (
 	ReverseAttr                      Attr = 7
 	ConcealAttr                      Attr = 8
 	StrikethroughAttr                Attr = 9
-	NoBoldAttr                       Attr = 21 // Some terminals treat this as double underline.
 	NormalIntensityAttr              Attr = 22
 	NoItalicAttr                     Attr = 23
 	NoUnderlineAttr                  Attr = 24
@@ -298,7 +292,6 @@ const (
 	reverseAttr                      = "7"
 	concealAttr                      = "8"
 	strikethroughAttr                = "9"
-	noBoldAttr                       = "21"
 	normalIntensityAttr              = "22"
 	noItalicAttr                     = "23"
 	noUnderlineAttr                  = "24"