1.VerbTo become sober; to cause to become sober (usually in terms of alcohol or drugs; sometimes figuratively)."She's in no state to go home by herself, so make sure she doesn't drink anything else, and she'll soon sober up.; A pot of black coffee ought to sober him up.; When the irrational exuberance finally ended and the central bank took away the punch bowl, the business world belatedly sobered up."