abrupt and complete withdrawal from the use of an addictive substance, as a narcotic drug, alcohol, or tobacco. ?

go cold turkey

to stop using an addictive substance abruptly and completely.

to undergo sudden and complete withdrawal from a habitual activity or behavior pattern.

to begin or do something without planning, preparation, or practice.

noun

abrupt withdrawal , crash , detox , detoxification , on the wagon , sudden withdrawal , taking the cure