1
general::
Immediate, complete withdrawal from something, especially an addictive substance; also, without planning or preparation. For example, My bad shoulder forced me to quit playing tennis cold turkey, or I'd never done any rock climbing, but decided to try it cold turkey. This term may have come from the earlier expression TALK TURKEY (for blunt speaking). At first used strictly for abrupt withdrawal from drugs or alcohol, it soon was transferred to quitting any habit or activity. [Early 1900s]
American Heritage Idioms
2
general::
Phrase(s): cold turkey
Sl. immediately; without tapering off or cutting down gradually. (See also go cold turkey. Originally drug slang. Now used of breaking any habit.) • Tom stopped smoking cold turkey. • She gave up her drinking habit cold turkey and had no ill effects.
McGrawhill's American Idioms And Phrasal Verbs