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

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

During the trial, prosecutors said investigators also found hemlock — a poisonous plant that can be fatal if ingested — in the family’s home, Courthouse News reported. — Nicole Acosta, PEOPLE, 10 July 2026

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

All of this played out against an increasingly poisonous political environment. — Eric Berger, ArsTechnica, 3 July 2026