/ ˈpɔɪzənəs; NAmE / adjective
1.
causing death or illness if swallowed or absorbed into the body
SYN toxic :
poisonous chemicals / plants
This gas is highly poisonous.
The leaves of certain trees are poisonous to cattle.
2.
( of animals and insects ) producing a poison that can cause death or illness if the animal or insect bites you
SYN venomous :
poisonous snakes
3.
extremely unpleasant or unfriendly :
the poisonous atmosphere in the office