Definition of “poisonous” - English Dictionary

british dictionary

“poisonous” in British English

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poisonousadjective

uk /ˈpɔɪ.zən.əs/ us /ˈpɔɪ.zən.əs/

B2 very harmful and able to cause illness or death:

poisonous chemicals
Can you tell the difference between poisonous mushrooms and edible varieties?

B2 A poisonous animal or insect uses poison in order to defend itself:

a poisonous snake

very unpleasant and unkind:

He said some poisonous things to me.

More examples

  • Carbon monoxide is a colourless, odourless, poisonous gas.
  • These normally harmless substances combine to form a highly poisonous gas.
  • Thousands of fish were killed as a result of a discharge of poisonous chemicals from a nearby factory.
  • Fungus can be poisonous.
  • The chemicals can be poisonous if ingested.

(Definition of “poisonous” from the Cambridge Advanced Learner's Dictionary & Thesaurus © Cambridge University Press)