1. A small dagger with a slim blade that is triangular or square in its cross section used for piercing or stabbing: When in the museum, Wilber saw a historical poniard in a showcase dating back to the Italian Renaissance.
2. Etymology: from Middle French poinard; from Old French poignal, "dagger"; literally, "anything grasped with the fist", from poing, "fist", from Latin pungus, "strike, hit".

To pierce or to stab someone with a small dagger (short knife with a pointed blade): In the news, there was a case of a man who poniarded a woman in the throat for no apparent reason while she was shopping in a grocery store.