source: Poison by Deathares on DeviantArt

a substance that is capable of causing the illness or death of a living organism when introduced or absorbed.

毒, 毒物, 毒薬 (!venomは動物･虫などの毒(液)

Chemistry a substance that reduces the activity of a catalyst.

Physics an additive or impurity in a nuclear reactor that slows a reaction by absorbing neutrons.

a person, idea, action, or situation that is considered to have a destructive or corrupting effect or influence:

(感情や考え方の)害になるもの, 悪影響を与えるもの

e.g. meanwhile he is spreading his poison over the Internet.

verb with object

administer poison to (a person or animal), either deliberately or accidentally:

〈人など〉に毒を盛る, …を毒殺する

e.g. someone had tried to poison me

e.g. (as noun poisoning) : symptoms of poisoning may include nausea, diarrhea, and vomiting

e.g. swans are being poisoned by lead from anglers' lines.

adulterate or contaminate (food or drink) with poison.

〈物〉に毒を入れる［塗る］

(usually as adjective poisoned) treat (a weapon or missile) with poison in order to augment its lethal effect.

prove harmful or destructive to:

〈人〉の心を毒する, 〈感情･考え方〉の害になる, …に悪影響を与える

e.g. his disgust had poisoned his attitude toward everyone.

Chemistry (of a substance) reduce the activity of (a catalyst).

informal used to ask someone what they would like to drink.

poisoner |ˈpoiz(ə)nər| noun

Middle English (denoting a harmful medicinal draft): from Old French poison ‘magic potion’, from Latin potio(n-) ‘potion’, related to potare ‘to drink’.