Poison is a substance that can harm or even kill you. Arsenic and cyanide are both types of poison—so stay away from them! Mean people can also be poison, so stay away from them too.

Poison refers to the harmful substance itself, or the act of giving it to someone. Poison often shows up in murder mysteries because it’s a sneaky way to get rid of someone. We also use poison metaphorically for things that tend to ruin something. A really obnoxious friend who always insists that he knows more than everyone else might poison the atmosphere at a dinner party. Jealousy can poison a good relationship.

Definitions of poison
  1. noun
    any substance that causes injury or illness or death of a living organism
    synonyms: poisonous substance, toxicant
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    a poisonous crystalline alkaloid extracted from the nightshade family; used as an antispasmodic and to dilate the eye pupil; also administered in large amounts as an antidote for organophosphate nerve agents or organophosphate insecticides
    a poisonous crystalline alkaloid (isometric with atropine but more potent); used to treat excess motility of the gastrointestinal tract
    a poisonous substance produced during the metabolism and growth of certain microorganisms and some higher plant and animal species
    an alkaloidal extract or tincture of the poisonous belladonna plant that is used medicinally
    ricin, ricin toxin
    a toxic protein extracted from castor beans; used as a chemical reagent; can be used as a bioweapon
    animal toxin, zootoxin
    a toxin resembling bacterial toxins in its antigenic properties that is found in the fluids of certain animals
    bacterial toxin
    any endotoxin or exotoxin formed in or elaborated by bacterial cells
    any substance that has a toxic effect on cells
    a toxin that is confined inside the microorganisms and is released only when the microorganisms are broken down or die
    a toxin that is secreted by microorganisms into the surrounding medium
    any toxin that affects the liver
    any toxin that affects the kidneys
    neurolysin, neurotoxin
    any toxin that affects neural tissues
    phytotoxin, plant toxin
    any substance produced by plants that is similar in its properties to extracellular bacterial toxin
    type of:
    a particular kind or species of matter with uniform properties
  2. noun
    anything that harms or destroys
    “the poison of fascism”
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    type of:
    the quality of causing destruction
  3. verb
    kill with poison
    “She poisoned her husband”
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    type of:
    cause to die; put to death, usually intentionally or knowingly
  4. verb
    add poison to
    synonyms: envenom
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    type of:
    alter, change, modify
    cause to change; make different; cause a transformation
  5. verb
    administer poison to
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    have an intoxicating effect on, of a drug
    type of:
    dose, drug
    administer a drug to
  6. verb
    kill by its poison
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    type of:
    cause to die; put to death, usually intentionally or knowingly
  7. verb
    spoil as if by poison
    poison someone's mind”
    poison the atmosphere in the office”
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    type of:
    corrupt, debase, debauch, demoralise, demoralize, deprave, misdirect, pervert, profane, subvert, vitiate
    corrupt morally or by intemperance or sensuality
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