poison

(noun) any substance that causes injury or illness or death of a living organism. Synonyms: toxicant, poisonous substance.

(noun) anything that harms or destroys. Example: "The poison of fascism."

(verb) spoil as if by poison. Examples: "Poison someone's mind." "Poison the atmosphere in the office."

(verb) kill with poison. Example: "She poisoned her husband."

(verb) add poison to. Synonyms: envenom. Example: "Her husband poisoned her drink in order to kill her."

(verb) kill by its poison. Example: "This mushrooms can poison."

(verb) administer poison to. Example: "She poisoned her husband but he did not die."