-stopper (thing that halts or prevents something); -blocker; -preventer
「止め」 has other readings with different meanings.
finishing blow; coup de grâce
(a) stop (e.g. in a timber joint, or at the end of a kanji stroke)
non-slip device (material, tread, etc.); non-skid; anti-slip; anti-skid
antidiarrheal; paregoric; obstipant