diff --git a/src/spell.h b/src/spell.h
index 085f18c..380e5ec 100644
--- a/src/spell.h
+++ b/src/spell.h
@@ -298,4 +298,8 @@
 SPELL_EXTERN spelltab_T   spelltab;
 SPELL_EXTERN int	  did_set_spelltab;
 
+// Values for "what" argument of spell_add_word()
+#define SPELL_ADD_GOOD	0
+#define SPELL_ADD_BAD	1
+#define SPELL_ADD_RARE	2
 #endif