'wake up' definitions:

Definition of 'wake up'

From: WordNet
verb
Cause to become awake or conscious; "He was roused by the drunken men in the street"; "Please wake me at 6 AM." [syn: awaken, wake, waken, rouse, wake up, arouse] [ant: cause to sleep]
verb
Stop sleeping; "She woke up to the sound of the alarm clock" [syn: wake up, awake, arouse, awaken, wake, come alive, waken] [ant: dope off, doze off, drift off, drop off, drowse off, fall asleep, flake out, nod off]

Synonyms of 'wake up'

From: Moby Thesaurus