diff --git a/share/man/man9/groupmember.9 b/share/man/man9/groupmember.9
--- a/share/man/man9/groupmember.9
+++ b/share/man/man9/groupmember.9
@@ -36,9 +36,9 @@
 .Sh SYNOPSIS
 .In sys/param.h
 .In sys/ucred.h
-.Ft int
+.Ft bool
 .Fn groupmember "gid_t gid" "struct ucred *cred"
-.Ft int
+.Ft bool
 .Fn realgroupmember "gid_t gid" "struct ucred *cred"
 .Sh DESCRIPTION
 The
@@ -59,9 +59,8 @@
 works the same except that it considers instead the real and supplementary
 groups, and not the effective one.
 .Sh RETURN VALUES
-If the
-.Fa gid
-is found, 1 is returned, otherwise 0.
+Returns whether the credentials indicate membership of the group
+.Fa gid .
 .Sh SEE ALSO
 .Xr getgroups 2
 .Xr setgroups 2