Pronunciation: (när-kot'ik),[key] —n. 1. any of a class of substances that blunt the senses, as opium, morphine, belladonna, and alcohol, that in large quantities produce euphoria, stupor, or coma, that when used constantly can cause habituation or addiction, and that are used in medicine to relieve pain, cause sedation, and induce sleep.
2. anything that exercises a soothing or numbing effect or influence: Television is a narcotic for many people.
—adj. 1. of or having the power to produce narcosis, as a drug.
2. pertaining to or of the nature of narcosis.
3. of or pertaining to narcotics or their use.
4. used by, or in the treatment of, narcotic addicts.