diff --git a/doc/pages/commands.asciidoc b/doc/pages/commands.asciidoc
index c9c84b96..50b235f7 100644
--- a/doc/pages/commands.asciidoc
+++ b/doc/pages/commands.asciidoc
@@ -319,7 +319,8 @@ but not really useful in that context.
     evaluated as if by source the first time *require-module <name>* is run.
 
 *-override*:::
-    allow the module to replace and existing one with the same name
+    allow the module to replace an existing one with the same name. Fails if
+    the module has already been evaluated.
 
 *require-module* <name>::
     guarantees the commands associated with *name* have been evaluated before