wake-up (n.) Look up wake-up at Dictionary.com
something that brings one to alertness or out of sleep, 1965, often in the 1960s in reference to a shot of heroin in the morning. Phrase wake-up call is attested from 1968, originally a call one received from the hotel desk in the morning. Verbal phrase wake up is from 1530s; earlier the adverb was out (late 14c.)