diff --git a/src/option.c b/src/option.c
index 5b6dbe3..fae10b6 100644
--- a/src/option.c
+++ b/src/option.c
@@ -2660,7 +2660,7 @@
     {"textwidth",   "tw",   P_NUM|P_VI_DEF|P_VIM|P_RBUF,
 			    (char_u *)&p_tw, PV_TW,
 			    {(char_u *)0L, (char_u *)0L} SCRIPTID_INIT},
-    {"thesaurus",   "tsr",  P_STRING|P_EXPAND|P_VI_DEF|P_ONECOMMA|P_NODUP,
+    {"thesaurus",   "tsr",  P_STRING|P_EXPAND|P_VI_DEF|P_ONECOMMA|P_NODUP|P_NDNAME,
 #ifdef FEAT_INS_EXPAND
 			    (char_u *)&p_tsr, PV_TSR,
 #else