poisonous
gb/pˈɔɪzənəs/ us/pˈɔɪzənəs/
B1
English
~ 8300
Senses
0 senses
adjective
B1
property
1
containing poison; toxic
Having something in it that can make you very sick or kill you if you eat, drink, breathe, or touch it.
Usage pattern:
[something] is poisonous; poisonous [noun]
Common mistake:
Learners often confuse "poisonous" and "venomous". "Poisonous" usually describes something that is dangerous if you eat, drink, or touch it (a poisonous plant or mushroom), while "venomous" is used for animals that inject poison through a bite or sting (a venomous snake or spider). In everyday speech, many people still say "poisonous snake", but in scientific or careful usage "venomous" is more accurate.
Synonyms
toxic (More formal and often used in scientific or technical contexts, especially about chemicals and waste.)
Antonyms
non-toxic (Used especially on labels or in safety information to say that something will not poison you.)
Collocations
poisonous plants
|poisonous mushrooms
|poisonous snake
|poisonous gas
|poisonous chemicals
|poisonous fumes
Themes
health
|science
|environment
|core_vocabulary
Examples
- These berries look nice, but they are actually extremely poisonous.
- The factory was shut down after it released poisonous gas into the air.
- Some snakes are harmless, but others carry poisonous venom that can kill a person in minutes.
- Children should learn to recognize common poisonous plants in the area.
- The report warned that the river contained poisonous chemicals from the mine.
Learner examples
- Do not eat those red mushrooms; they are poisonous.
- The smoke from the fire was poisonous, so we wore masks.
- That green snake is poisonous, so stay away from it.
- The water is poisonous because of the factory waste.
- Some cleaning liquids are poisonous if you drink them.
adjective
B2
property
2
extremely harmful or destructive
Very bad and harmful in a way that hurts people, groups, or society, not the body.
Usage pattern:
poisonous [thing/abstract noun]
Common mistake:
Learners may think "poisonous" can only describe physical things like plants or gas. In modern English, it is also very common for abstract things like "poisonous culture" or "poisonous politics" to describe serious non-physical harm.
Synonyms
toxic (Very common in modern speech for harmful cultures, environments, or behaviors; slightly more informal in this figurative sense.)
Antonyms
healthy (Emphasizes that something supports good emotional or social well-being instead of harming it.)
Collocations
poisonous culture
|poisonous influence
|poisonous ideology
|poisonous politics
|poisonous environment
Themes
society
|emotions
|politics
|relationships
|core_vocabulary
Examples
- Many employees left because of the poisonous culture in the company.
- The documentary exposed the poisonous influence of hate groups on young people.
- Some commentators argue that the debate was fueled by a poisonous mix of fear and misinformation.
- He warned that social media can create a poisonous environment where lies spread quickly.
- The novel shows how a poisonous ideology can slowly destroy a community.
Learner examples
- She grew up in a poisonous family culture full of lies and control.
- There is a poisonous atmosphere in the team because people do not trust each other.
- The leader's poisonous ideas divided the country.
- Many people are tired of the poisonous politics on television.
- Gossip can create a poisonous environment at school.
adjective
B2
property
3
full of hatred or malice
Showing very strong hate or anger and trying to hurt another person with words or actions.
Usage pattern:
poisonous [remark/relationship/look]
Common mistake:
Learners sometimes use "angry" or "bad" for all negative behavior. "Poisonous" here is stronger and suggests deep, long-lasting hate or harm, especially in speech or relationships.
Synonyms
spiteful (Focuses strongly on the desire to hurt someone emotionally, often in small but cruel ways.)
Antonyms
kind (Highlights the opposite emotional quality: wanting to help and not hurt other people.)
Collocations
poisonous remark
|poisonous comment
|poisonous tone
|poisonous relationship
|poisonous look
Themes
emotions
|relationships
|communication
Examples
- She shot him a poisonous look and walked out of the room.
- Their divorce turned into a long, poisonous battle in public.
- He is known for his poisonous remarks about anyone who disagrees with him.
- The emails between the two colleagues became increasingly poisonous over time.
- What began as a small disagreement slowly grew into a poisonous relationship.
Learner examples
- He made a poisonous comment about her work.
- They have a poisonous relationship and fight every day.
- She spoke to him in a poisonous voice.
- After the meeting, he sent a poisonous message to his boss.
- Her smile looked friendly, but her eyes were poisonous.
Grammar
Dictionary form
poisonous
IPA
GB/pˈɔɪzənəs/
US/pˈɔɪzənəs/
Syllables & stress
pois - on - ous (3 syllables)
Stress on 1st syllable (pois)
Word forms
Adjective
- Base: poisonous
Word family
Expressions
poisonous atmosphere
1/pˈɔɪzənəs ˈætməsfˌɪɹ/
fixed phrase
very hostile mood in a place
A place or group feels very angry, hateful, or unfriendly, so people feel bad or afraid there.
Examples
- There was a poisonous atmosphere in the office after the layoffs were announced.
- The poisonous atmosphere in the classroom made it hard for students to speak freely.
- Years of conflict created a poisonous atmosphere in the community.
poisonous gas
1/pˈɔɪzənəs ɡˈæs/
fixed phrase
gas that can poison people
Gas in the air that can make you very sick or kill you if you breathe it.
Examples
- The mine filled with poisonous gas after the explosion.
- Workers wear special masks to protect themselves from poisonous gas.
- The leak released poisonous gas into nearby homes.
poisonous relationship
1/pˈɔɪzənəs ɹilˈeɪʃənʃˌɪp/
fixed phrase
emotionally harmful relationship
A relationship between people that often hurts them emotionally and is very unhealthy for them.
Examples
- She finally ended the poisonous relationship and moved out.
- Therapists warned them that they were stuck in a poisonous relationship.
- Growing up around her parents' poisonous relationship affected her trust in others.
poisonous remark
1/pˈɔɪzənəs ɹɪmˈɑɹk/
fixed phrase
deeply hurtful or malicious comment
A very unkind comment that is meant to hurt or attack someone strongly.
Examples
- He is famous for his short, poisonous remarks on social media.
- Her poisonous remark about his family shocked everyone at the table.
- The article was full of poisonous remarks aimed at the mayor.