- Containing sufficient poison to be dangerous to touch or ingest.
- While highly poisonous to dogs, this substance is completely harmless if ingested by humans.
- 2003, Charles L. Fergus, Common Edible and Poisonous Mushrooms of the Northeast, Stackpole Books, →ISBN, page 77:
- I had picked a mushroom so poisonous that particles of it, stuck to my fingers and accidentally swallowed, could have made me deathly ill, and a piece the size of my thumb could have killed me.
- (figuratively) Negative, harmful.
- 2013, Kylie Griffin, Allegiance Sworn, Penguin, →ISBN:
- He didn't want to end up like his grandfather, bitter and intractable, consumed in his hatred like an addict on haze — a poisonous attitude that would possess him all his remaining years.
- Synonym: toxic
Some speakers make a distinction between poisonous (releasing toxins when eaten), and venomous (releasing toxins (known as venom in this case) by biting a target), especially in non-colloquial speech.
containing sufficient poison to be dangerous