noun. A colorless, poisonous alkaloid, C₁₀H₁₄N₂, derived from the tobacco plant and used as an insecticide. It is the substance in tobacco to which smokers can become addicted.

noun. A volatile alkaloid base (C₁₀H₁₄N₂) obtained from tobacco.

noun. An alkaloid which is the active principle of tobacco (C10H14N2). It occurs in tobacco plants (Nicotiana tabacum and Nicotiana rusticum) to the extent of 2 to 8%, in combination with malic acid or citric acid. It is a colorless, transparent, oily liquid, having an acrid odor, and an acrid burning taste. It is intensely poisonous. The apparently addictive effects of tobacco smoking have been ascribed largely to the effect of nicotine, and the controlled administration of nicotine on various forms has been used as a technique for assisting efforts to stop the smoking habit.

noun. An alkaloid (C10H14N2), commonly occurring in the tobacco plant. In small doses it is a habit-forming stimulant; in larger doses it is toxic and is often used in insecticides.

noun. an alkaloid poison that occurs in tobacco; used in medicine and as an insecticide

"The vast majority of smokers start in childhood and then find it very difficult to quit because nicotine is addictive."

alkaloid  phytotoxin  plant toxin  pressor  vasoconstrictive  

addiction  amphetamine  arsenic  aspirin  atropine