Synonyms of poisonous

poisonous

adjective

ˈpȯiz-nəs 

as in poisoned

containing or contaminated with a substance capable of injuring or killing a living thing

some evil person was leaving out poisonous meat for neighborhood dogs to eat

Synonyms & Similar Words

• poisoned
• poison
• toxic
• venomous
• harmful
• infective
• infectious
• envenomed
• malignant
• injurious
• pathogenic
• pestilential
• virulent
• lethal
• deleterious
• baneful
• noxious
• contagious
• unhealthful
• hurtful
• fatal
• deadly
• unwholesome
• nocuous
• unhealthy
• pestilent
• calamitous
• murderous
• fell

Antonyms & Near Antonyms

• nontoxic
• beneficial
• helpful
• healthy
• healthful
• wholesome
• nonpoisonous
• harmless
• curative
• remedial
• salutary
• benign
• palliative
• salubrious
• innocuous
• nonvenomous
• inoffensive
• nonfatal
• nonlethal

Example Sentences

Recent Examples of poisonous

How plants poisonous to dogs cause harm Not all toxic plants affect dogs the same way, but many share similar chemicals that attack the digestive system. — Ryan Brennan, Fort Worth Star-Telegram, 15 July 2026

Matters got worse after passersby with guns pinged holes in some of the barrels, and the poisonous stuff soaked about 15 feet down into the desert soil. — Patt Morrison, Los Angeles Times, 15 July 2026

The pattern looks like the skin of a poisonous frog poking its head out from under its hiding place. — Jasmine Washington, InStyle, 15 July 2026

Shrouded completely in a thick, poisonous cloud cover, its surface is obviously impossible to observe. — Mike Lynch, Twin Cities, 5 July 2026