poisonnoun/ˈpɔɪ.zən/

• 1

  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

  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

  informalAn 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

  chemistrynatural-sciencesphysical-sciencesAny 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.

poisonverb/ˈpɔɪ.zən/

• 1

  To use poison to kill or paralyse (somebody).

  • The assassin poisoned the king.
• 2

  To pollute; to cause to become poisonous.

  • That factory is poisoning the river.
• 3

  To cause to become much worse.

  • Suspicion will poison their relationship.
  • He poisoned the mood in the room with his non-stop criticism.
• 4

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

  • She's poisoned him against all his old friends.
• 5

  chemistrynatural-sciencesphysical-sciencesTo inhibit the catalytic activity of.

• 6

  computingengineeringmathematicsTo 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.