n. & v.
--n.
1. a substance that when introduced into or absorbed by a living organism causes death or injury, esp. one that kills by rapid action even in a small quantity.
2 colloq. a harmful influence or principle etc.
3 Physics & Chem. a substance that interferes with the normal progress of a nuclear reaction, chain reaction, catalytic reaction, etc.
--v.tr.
1. administer poison to (a person or animal).
2 kill or injure or infect with poison.
3 infect (air, water, etc.) with poison.
4 (esp. as poisoned adj.) treat (a weapon) with poison.
5 corrupt or pervert (a person or mind).
6 spoil or destroy (a person's pleasure etc.).
7 render (land etc.) foul and unfit for its purpose by a noxious application etc.
Phrases and idioms:
poison gas GAS n. 4. poison ivy a N. American climbing plant, Rhus toxicodendron, secreting an irritant oil from its leaves. poison-pen letter an anonymous libellous or abusive letter.
Derivatives:
poisoner n. poisonous adj. poisonously adv.
Etymology: ME f. OF poison, poisonner (as POTION)