boy what up Share definition Flag a phrase used to greet other people. orig. by @kermit_nofrog "Boy what up!!! I ain't seen you in a hot minute!!! We going hard at Club Vegas VIP tonight!!!" boy what up by @CLUB_VEGAS_VIP December 23, 2011 0 0 Get merch Get the boy what up mug. Buy Now — $32.95 See more merch