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" (同)nut, freak, junkie, junky
someone who is physiologically dependent on a substance; abrupt deprivation of the substance produces withdrawal symptoms
to cause (someone or oneself) to become dependent (on something, especially a narcotic drug) (同)hook