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

Astronauts bring them on journeys to keep an eye on whether or not the water filtration systems are working, much the way miners used to take canaries down to the coal mines to check for poisonous gas leaks. — Leslie Felperin, HollywoodReporter, 18 Sep. 2026

All parts of poison hemlock are poisonous if ingested, and exposure can be fatal. — Sj McShane, Martha Stewart, 18 Sep. 2026

Spanish bluebells contain saponins, which smell and taste like soap, as well as poisonous cardiac glycosides. — ABC News, 8 Sep. 2026

As Anna covers for Fyodor’s addiction and increasingly unstable professional behavior, her devotion starts to look poisonous for them both. — Alison Foreman, IndieWire, 5 Sep. 2026