diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6fe7275d..bbfb22de 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Change Log
 
+## (In Development)
+
+*  Make the ispunct ctype compatibility implementation conformant.
+
 ## 10.0.0 - 2017-06-25
 
 *  Add `iswblank` and `iswxdigit` compatibility.
diff --git a/src/ctype.c b/src/ctype.c
index 42bb9f58..ac6a37ea 100644
--- a/src/ctype.c
+++ b/src/ctype.c
@@ -1,6 +1,6 @@
 /* ctype-style APIs.
  *
- * Copyright (C) 2012-2017 Reece H. Dunn
+ * Copyright (C) 2012-2018 Reece H. Dunn
  *
  * This file is part of ucd-tools.
  *
@@ -151,19 +151,7 @@ int ucd_isprint(codepoint_t c)
 
 int ucd_ispunct(codepoint_t c)
 {
-	switch (ucd_lookup_category(c))
-	{
-	case UCD_CATEGORY_Pc:
-	case UCD_CATEGORY_Pd:
-	case UCD_CATEGORY_Pe:
-	case UCD_CATEGORY_Pf:
-	case UCD_CATEGORY_Pi:
-	case UCD_CATEGORY_Po:
-	case UCD_CATEGORY_Ps:
-		return 1;
-	default:
-		return 0;
-	}
+	return ucd_isgraph(c) && !ucd_isalnum(c);
 }
 
 int ucd_isspace(codepoint_t c)
diff --git a/tools/printdata.py b/tools/printdata.py
index 513a890c..e7bdc9a1 100755
--- a/tools/printdata.py
+++ b/tools/printdata.py
@@ -78,10 +78,7 @@ def isblank(data): # word separator
 		return 0
 
 def ispunct(data):
-	if data.get('GeneralCategory', 'Cn')[0] in 'P':
-		return 1
-	else:
-		return 0
+	return 1 if isgraph(data) and not isalnum(data) else 0
 
 def isprint(data):
 	if data.get('GeneralCategory', 'Cn')[0] in 'LMNPSZ': # not in 'CI'