The term “cold turkey” is an American idiom which means “to quit instantly,” or “to talk plainly.” Most people use the term in the sense of quitting drugs, with the cold turkey approach being one method to use in an attempt to beat a drug addiction. Quitting cold turkey is definitely not for everyone, as the symptoms of withdrawal can be very severe, since no tapering of the dosage is involved. In fact, in some cases an abrupt cessation of drug use can lead to death due to systemic shock.
This term appears to have emerged around 1920s. There are a number of theories about its origins. Some people say that the idiom is a reference to literal cold turkey, a dish which is served just as it is, without any preparation or discussion. Others have suggested that the term relates to the appearance of people who are struggling with withdrawal, since people tend to get pale and covered in goosebumps, exactly like a cold piece of turkey.
However, the origins of this idiom are actually much less imaginative. It's derived from “talk turkey,” an older slang term used to describe getting down to business without any prevarications or messing around. No one is really certain about why turkeys have come to be associated with getting to the point quickly, although it may have something to do with the fact that the turkey is an icon of the Puritan lifestyle, which was allegedly simple and plain.
When someone goes cold turkey, he or she immediately abandons a habit, with no preparation or tapering off. Some people think that this method is very effective for treatment of drug abuse, while others feel that it may result in recidivism, as people are not gradually eased into quitting. One advantage of quitting cold turkey is that it requires no preparation, meaning that someone can wake up one morning and decide to quit then and there, as opposed to someone who embarks on a lengthy treatment plan, which can lead to a loss of motivation over time.
Some people also use “cold turkey” in the same sense as “talk turkey,” meaning a conversation which is simple, clear, and to the point. In both senses, the idiom is associated with bluntness, and a desire to get something over with quickly. In some regions of the United States, clarity and simplicity in communications are highly valued, with people being actively encouraged to talk turkey rather than dancing around a point.