MESS AROUND

{v. phr.} 1. To engage in idle or purposeless activity. * /Come on, you guys, - start doing some work, don't just mess around all day!/ 2. {vulgar} To be promiscuous; to indulge in sex with little discrimination as to who the partner is. * /Allen needs straightening out; he's been messing around with the whole female population of his class./ Compare: FOOL AROUND.