poisonous
POY-zuh-nuhs
Poisonous (adj) means containing enough poison to harm or kill if touched, eaten, or breathed in. Example: “Some poisonous berries look almost identical to edible ones.”
adj
1
Containing enough poison to harm or kill if touched, eaten, or breathed in.
"Some poisonous berries look almost identical to edible ones."
"The factory leaked poisonous gas into the air."
"Never touch that poisonous plant in the garden without wearing gloves."
2
Deeply harmful, especially to a person's attitude or a relationship.
"He left the company because of its poisonous work culture."
"Constant gossip had a poisonous effect on the whole friendship group."
"The coach said that a poisonous attitude can ruin an entire team."
How to use poisonous
Learner’s notesIn plain EnglishCapable of causing serious harm — either physically toxic, or (figuratively) toxic to a relationship or environment.
Common mistake
In everyday English, "poisonous" and "venomous" are often used interchangeably, though strictly venomous describes animals that inject poison by biting or stinging, while poisonous describes things harmful if touched or eaten.
Easily confused with
Common pairings
poisonous snake
poisonous gas
poisonous atmosphere
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Word forms
- Comparative
- more poisonous
- Superlative
- most poisonous
Fill the gap
Can you complete this real example?
Some _____ berries look almost identical to edible ones.
Etymology
From poison + the adjective suffix -ous.
Synonyms
View more →Antonyms
Related words
Rhymes for poisonous
See all rhymes for poisonous →Frequently asked questions
What does “poisonous” mean?
The word “poisonous” means containing enough poison to harm or kill if touched, eaten, or breathed in. In plain terms, capable of causing serious harm — either physically toxic, or (figuratively) toxic to a relationship or environment.
How do you pronounce “poisonous”?
“Poisonous” is pronounced POY-zuh-nuhs (/ˈpɔɪzənəs/ in IPA).
How do you use “poisonous” in a sentence?
Here is “poisonous” used in a sentence: “Some poisonous berries look almost identical to edible ones.”
What part of speech is “poisonous”?
“Poisonous” is an adjective.
Is “poisonous” a common word?
“Poisonous” is an uncommon word in modern English, usually learned at around the B1 level.
How many meanings does “poisonous” have?
“Poisonous” has 2 distinct senses listed in this dictionary. The most common is: containing enough poison to harm or kill if touched, eaten, or breathed in.
What is the difference between poisonous and venomous?
Poisonous describes something harmful if touched, eaten, or breathed in, while venomous specifically describes an animal that injects toxins through a bite or sting. A snake that bites and injects toxin is venomous, but a plant that is harmful to eat is poisonous, not venomous.
What is the difference between poisonous and toxic?
The two words overlap closely, but poisonous is most often used for substances or organisms capable of causing harm or death if ingested, touched, or inhaled, while toxic is a broader term that can also describe harmful environments, chemicals, or behavior. In practice, people frequently use them interchangeably.
Can "poisonous" describe something other than a physical substance?
Yes, poisonous is often used figuratively to describe something deeply harmful to a person's attitude or a relationship, such as a poisonous rumor or a poisonous work environment. This figurative use is very common alongside the literal, physical sense.
