Dictionary.com
Thesaurus.com
Synonyms

poisonous

American  
[poi-zuh-nuhs] / ˈpɔɪ zə nəs /

adjective

  1. full of or containing poison.

    poisonous air; a poisonous substance.

  2. harmful; destructive.

    poisonous to animals; poisonous rumors.

  3. deeply malicious; malevolent.

    poisonous efforts.


poisonous British  
/ ˈpɔɪzənəs /

adjective

  1. having the effects or qualities of a poison

  2. capable of killing or inflicting injury; venomous

  3. corruptive or malicious

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Other Word Forms

  • nonpoisonous adjective
  • nonpoisonously adverb
  • nonpoisonousness noun
  • poisonously adverb
  • poisonousness noun
  • semipoisonous adjective
  • semipoisonously adverb
  • unpoisonous adjective
  • unpoisonously adverb

Etymology

Origin of poisonous

First recorded in 1565–75; poison + -ous

Compare meaning

How does poisonous compare to similar and commonly confused words? Explore the most common comparisons:

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Perhaps, but it also gave an immediacy bordering on desperation to a story of teenage identity, poisonous social media and murder.

From The Wall Street Journal

Part of the reasoning in 2018 was site investigations found the ground underlain with peat deposits, as well as toxic and phytotoxic - meaning poisonous to plants - risk from shallow soils.

From BBC

Its poisonous thorns also injure livestock, leaving them too weak to roam for food, he added.

From Barron's

Promotion of knowledge and understanding has given way to inculcation of a poisonous fringe ideology.

From The Wall Street Journal

The scientists discovered that the reaction between hydrogen sulfide -- a poisonous gas -- and solid iron minerals is not only a chemical process, but also a biological one.

From Science Daily