Boyd’s Bible Dictionary:
(hammer). Heavy wooden hammer (Prov. 25:18). Battle ax (Jer. 51:20).
Concise Bible Dictionary:
Mallet or war-club for breaking in pieces or attacking (Prov. 25:18).
Modern Mallet
Strong’s Dictionary of Hebrew Words:
Transliteration:
mephiyts
Meaning:
from 6327; a breaker, i.e. mallet