1. a person or thing that ruins or spoils.
2. a deadly poison (often used in combination, as in the names of poisonous plants).
3. death; destruction; ruin.
4. Obsolete: that which causes death or destroys life.
Etymology: Middle English; Old English bana - slayer; cognate with Old Norse bani - death, murderer, Old Frisian bona - murder, Old Saxon bano - murderer, Old High German bano - slayer, bana - death; akin to Old English benn, Gothic banja - wound.