1. A substance that causes injury, illness, or death, especially by chemical means.
2. Something destructive or fatal.
3. Chemistry A substance that inhibits another substance or a reaction: a catalyst poison.
tr.v. poi·soned, poi·son·ing, poi·sons
1. To kill or harm with poison.
2. To put poison on or into: poisoning arrows; poisoned the drink.
a. To pollute: Noxious fumes poison the air. See Synonyms at contaminate.
b. To have a harmful influence on; corrupt: Jealousy poisoned their friendship.
4. Chemistry & Physics To inhibit (a substance or reaction).
[Middle English, from Old French, from Latin pōtiō, pōtiōn-, drink; see pō(i)- in the Appendix of Indo-European roots.]
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