a fuckboy is someone who aint about shit. he is almost always calling someone else a fuckboy, when he in turn, has not right in doing so. he is also probably a puta, and was probably named a fuckboy name at birth, such as daniel.
daniel: "ur a fuckboy bich"
chris: "thats weird cuz you are a fuckboy and have no right in calling anyone else a fuckboy"
daniel: "huh, yea right, better check your hypothesis!"
chris: *pulls up this entry from urban dictionary*