poison

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A substance that causes injury, illness, or death, especially by chemical means.
• noun Something destructive or fatal.
• noun Chemistry A substance that inhibits another substance or a reaction.
• transitive verb To kill or harm with poison.
• transitive verb To put poison on or into.
• transitive verb To pollute: synonym: contaminate.
• transitive verb To have a harmful influence on; corrupt.
• transitive verb Chemistry & Physics To inhibit (a substance or reaction).
• adjective Poisonous.

from The Century Dictionary.

• To infect with poison; put poison into or upon; add poison to: as, to poison an arrow.
• To administer poison to; attack, injure, or kill by poison.
• To taint; mar; impair; vitiate; corrupt.
• noun A drink; a draught; a potion.
• noun Any substance which, introduced into the living organism directly, tends to destroy the life or impair the health of that organism.
• noun Hence, that which taints or destroys moral purity or health or comfort: as, the poison of evil example.

from the GNU version of the Collaborative International Dictionary of English.

• transitive verb To put poison upon or into; to infect with poison
• transitive verb To injure or kill by poison; to administer poison to.
• transitive verb To taint; to corrupt; to vitiate
• intransitive verb To act as, or convey, a poison.
• noun Any agent which, when introduced into the animal organism, is capable of producing a morbid, noxious, or deadly effect upon it
• noun That which taints or destroys moral purity or health
• noun (Bot.), [U. S.] The poison sumac (Rhus venenata)
• noun (Bot.) poison sumac.
• noun (Zoöl.) one of the superior maxillary teeth of some species of serpents, which, besides having the cavity for the pulp, is either perforated or grooved by a longitudinal canal, at the lower end of which the duct of the poison gland terminates. See Illust. under Fang.
• noun (Biol.) a gland, in animals or plants, which secretes an acrid or venomous matter, that is conveyed along an organ capable of inflicting a wound.
• noun (Bot.) a poisonous umbelliferous plant (Conium maculatum). See Hemlock.
• noun (Bot.) a poisonous climbing plant (formerly Rhus Toxicodendron, or Rhus radicans, now classified as Toxicodendron radicans) of North America. It is common as a climbing vine, especially found on tree trunks, or walls, or as a low, spreading vine or as a shrub. As a low vine it grows well in lightly shaded areas, recognizable by growing in clusters of three leaves. Its leaves are trifoliate, rhombic-ovate, and variously notched. Its form varies slightly from location to location, leading to some speculation that it may consist of more than one species. Many people are poisoned by it, though some appear resistant to its effects. Touching the leaves may leave a residue of an oil on the skin, and if not washed off quickly, sensitive areas of skin become reddened and develop multiple small blisters, lasting for several days to several weeks, and causing a persistent itch. The toxic reaction is due to an oil, present in all parts of the plant except the pollen, called urushiol, the active component of which is the compound pentadecylacatechol (according to Charles H. Booras). See Poison sumac. It is related to poison oak, and is also called mercury.
• noun (Bot.) The tree which yields this seed (Strychnos Nuxvomica). It is found on the Malabar and Coromandel coasts.
• noun (Bot.) a dermatitis-producing plant often lumped together with the poison ivy (Toxicodendron radicans) in common terminology, but more properly distinguished as the more shrubby Toxicodendron quercifolium (syn. Toxicodendron diversilobum), common in California and Oregon. Opinion varies as to whether the poison oak and poison ivy are only variants of a single species. See poison ivy, above.
• noun (Zoöl.) Same as Poison gland, above. See Illust. under Fang.
• noun (Bot.) a poisonous shrub formerly considered to be of the genus Rhus (Rhus venenata), but now classified as Toxicodendron vernix; -- also called poison ash, poison dogwood, and poison elder. It has pinnate leaves on graceful and slender common petioles, and usually grows in swampy places. Both this plant and the poison ivy (Toxicodendron radicans, formerly Rhus Toxicodendron) have clusters of smooth greenish white berries, while the red-fruited species of this genus are harmless. The tree (Rhus vernicifera) which yields the celebrated Japan lacquer is almost identical with the poison sumac, and is also very poisonous. The juice of the poison sumac also forms a lacquer similar to that of Japan.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A substance that is harmful or lethal to a living organism.
• noun Something that harms a person or thing.
• noun A drink; liquor.
• verb transitive To use poison to kill or paralyse somebody
• verb transitive To pollute; to cause some part of the environment to become poisonous
• verb transitive To cause something to become much worse
• verb transitive To cause someone to hate or to have unfair negative opinions

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• verb add poison to
• verb administer poison to
• noun anything that harms or destroys
• verb kill with poison
• noun any substance that causes injury or illness or death of a living organism
• verb kill by its poison
• verb spoil as if by poison