muss up

muss up

To cause something to become disheveled or untidy, especially one's hair. A noun or pronoun can be used between "muss" and "up." I just spent an hour getting my hair exactly how I want it, so don't go mussing it up like that! Please don't muss your hair up before you get your pictures taken for school.
See also: up

muss someone or something up

to put someone or something into disarray. Don't muss me up! You mussed up my hair. I'm afraid I mussed myself up a little.
See also: up
References in periodicals archive ?
But he has been known to muss up his hair when trying to make a point.
Bears (-1) at Redskins: In first Jimmy Johnson Bowl, former top Cowboys assistants Dave Wannstedt and Norv Turner vie for right to fly to Disney World and muss up their former boss's hair.