'addict' definitions:

Definition of 'addict'

From: WordNet
noun
Someone who is so ardently devoted to something that it resembles an addiction; "a golf addict"; "a car nut"; "a bodybuilding freak"; "a news junkie" [syn: addict, nut, freak, junkie, junky]
noun
Someone who is physiologically dependent on a substance; abrupt deprivation of the substance produces withdrawal symptoms
verb
To cause (someone or oneself) to become dependent (on something, especially a narcotic drug) [syn: addict, hook]