1 causing death or illness if you eat or drink it （吃或喝会）引起中毒的

2 (used about animals, etc) producing and using poison to attack its enemies （指动物等）以毒物攻击敌人的，有毒的: He was bitten by a poisonous snake. 他给毒蛇咬了。

3 very unpleasant and intended to upset sb 令人厌恶的；恶意的；恶毒的: She wrote him a poisonous letter criticizing his behaviour. 她给他写了一封极不客气的信，批评他的行为。