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

Eucalyptus oil and fresh leaves are poisonous when ingested or inhaled. — Sarah Bence, Verywell Health, 25 Aug. 2026

For this reason, these poisonous mushrooms are more commonly confused with other types of edible mushrooms like chicken of the woods and chanterelles (more on these in a minute). — Katie Hill, Outdoor Life, 6 Aug. 2026

Perhaps ducks had been used as bio-processors, feeding on toads and metabolizing their poisonous compounds so that humans could safely consume them. — Kimon De Greef, Longreads, 4 Aug. 2026

Not all pufferfish are poisonous, but the vast majority contain a lethal neurotoxin called tetrodotoxin in their internal organs and skin. — Teresa Mull, FOXNews.com, 1 Aug. 2026