It was always my understanding that describing someone as a "weapon" was a (generally benign) insult: they behave in a manner that makes them a danger to themselves or others. Recently, however, I heard a woman refer to herself as a weapon, meaning "extremely attractive", a meaning that only makes sense in the world of Boyfriend Dungeon, a dungeon battler-meets-dating sim where your love interests are both extremely attractive and literally weapons. As in swords and that.