Definitions of poison:

• noun:   anything that harms or destroys

  Example: "The poison of fascism"

• noun:   any substance that causes injury or illness or death of a living organism
• verb:   spoil as if by poison

  Example: "Poison someone's mind"

• verb:   add poison to

  Example: "Her husband poisoned her drink in order to kill her"

• verb:   administer poison to

  Example: "She poisoned her husband but he did not die"

• verb:   kill with poison

  Example: "She poisoned her husband"

• verb:   kill by its poison