poison

noun

1. (countable, uncountable)A substance that is harmful or lethal to a living organism when ingested.

   “Near-synonym: (loosely) venom”

   “We used a poison to kill the weeds.”

2. (countable, figuratively, uncountable)Anything harmful to a person or thing.

   “Gossip is a malicious poison.”

   “Awaie with the Rebels ſuffer them not to ſpeake, His words are poyſon in the eares of the people, […]”

3. (countable, idiomatic, informal, uncountable)An alcoholic drink. (Mainly in the phrases "name your poison" and "what's your poison?")

   “— What's your poison? — I'll have a glass of whiskey.”

4. (countable, uncountable)Any substance that inhibits catalytic activity.

   “The temperature effect of poisons. The influence of poison on the catalyst can be different with the change of reaction conditions.”

verb

1. (transitive)To use poison to kill or paralyse (somebody).

   “The assassin poisoned the king.”

2. (transitive)To pollute; to cause to become poisonous.

   “That factory is poisoning the river.”

3. (transitive)To cause to become much worse.

   “Suspicion will poison their relationship.”

   “He poisoned the mood in the room with his non-stop criticism.”

4. (transitive)To cause (someone) to hate or to have unfair negative opinions.

   “She's poisoned him against all his old friends.”

5. To inhibit the catalytic activity of.
6. (transitive)To place false or malicious data into (a cache, etc.) as part of an exploit.

   “In this technique, the hacker poisons the cache to launch malware into Web pages.”