A male who acts like he cares about you, but really only cares about pussy. He always asks for nudies, and just wants sex. When you start to have feelings for him, he peaces out.
Joan: How are things with Joey?
Susie: IDK, He keeps asking for nudes, and then he ignores me for days if I ask him to hang out.
Joan: oh, So he's a fuckboy...
An asshole who has lots of girls in his phone and hides it from his girlfriend and always says "Shes the one". He always has a backup on girls because he plays them all.
Evolutionary rejects of the male gender who have basically had their brains taken over by their dicks. They are "brain-dead" and their true selves are hopelessly trapped and subdued by their dicks. Their dicks basically call the shots of every little thing they do with their lives. The only known way to free the trapped poor soul is to cut off their dicks or their testes.
Me: Stop being a fuckboy Adam!
Friend: You can't to a fuckboy like that. You might as well talk to his dick.