Meaning & use
poisonous
Last updated
Meanings
adjectivecomparable
Containing a substance that can make people or animals seriously ill or kill them if eaten, touched, or breathed in.
Grammar: Can come before a noun or after be: a poisonous plant, the berries are poisonous.
Patterns
- poisonous to someone
- be poisonous
Some wild mushrooms look harmless but are highly poisonous.
Keep cleaning products away from children because they are poisonous.
The leaves of this plant are poisonous to dogs.
adjectivecomparablefigurative
Full of hatred or spite and likely to damage relationships or the atmosphere in a group.
Grammar: Used figuratively, usually before a noun: a poisonous rumor.
The poisonous gossip in the office drove two people to quit.
He wrote a poisonous email that split the committee.
Word forms
| comparative | more poisonous |
|---|---|
| superlative | most poisonous |
Common combinations
- highly poisonous
- The fumes are highly poisonous in a closed room.
- poisonous snake
- We were warned about poisonous snakes on the trail.
- poisonous to humans
- The berries are poisonous to humans.
- a poisonous atmosphere
- Constant blame created a poisonous atmosphere at work.
Synonyms and how they differ
- toxic
- Often used for chemicals and pollution, and also common in figurative uses like toxic workplace.
- venomous
- Only for animals that inject poison by biting or stinging; poisonous is harmful when eaten or touched.
- deadly
- Stresses that something can kill, but does not say how it harms.
Opposites
Word family
Commonly confused: poisonous or venomous?
poisonous vs venomous
A snake that bites and injects toxin is venomous; a plant you must not eat is poisonous.
Practice
Which word is best for a plant that makes you ill if you eat its berries?
Choose one answer.
Poisonous describes things that harm when eaten or touched. Venomous is only for animals that inject toxin by biting or stinging.
Make it your own
Write a sentence using “poisonous”, then check it and compare it with the examples above.