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

Consuming this toxin can release poisonous hydrogen cyanide into the bloodstream. — Carrie Madormo, Verywell Health, 30 June 2026

The upstairs Death by Natural Causes exhibit, in partnership with the Houston Museum of Natural Science, opens June 27 and explores poisonous plants and animals. — Sacbee.com, 29 June 2026

Berlin — Authorities across Germany have been battling an aggressive outbreak of poisonous caterpillars, which can cause severe health issues and have led to the closure of parks and other outdoor spaces, including in Berlin. — Sophie Tanno, CNN Money, 23 June 2026

Every part of the tree is poisonous, including the small round manchineel fruits, which are known to be fatal if ingested. — Steve Bender, Southern Living, 21 June 2026