Recently becoming popular from the idea it is a boy whose only goal in life is to fuck ANY pussy that walks with little regard towards feelings/health. While this is true, it is also simultaneously true that a fuckboy is the boy in a prison clique that takes it up the ass. Both indicate that regardless of age, they are still considered a boy rather than a man because of their immaturity towards sex and their constant need for it, whether he is trying to fuck or getting fucked.
Fuckboys are incredibly easy to spot. In the real world, any boy asking a woman to "send nudes" is a fuckboy. Profile pictures consist of them grabbing their micropenises with their tongue sticking out through a nasty-looking snarl or them biting their lips with eyes directed downwards as if they were "checking out" a woman. Fuck boys have been known to think that they think they are better than everyone else, are good looking, and that any woman would be lucky to have sex with them but many studies have been done actually proving the exact opposite to be true by all accounts. In prison, they are easily spot because it will look like they have a diaper on from all the toilet paper they have shoved in their pants to help soak up blood. If still unsure - pay attention to a fuckboy you are having trouble identifying while they sit down - it will take a considerably longer time than others around him and you might even be able to notice some wincing in the face if you are close enough.
Steve: "Once a fuckboy, always a fuckboy.."
Megan: "I'm glad I realized that years ago when he asked me to send nudes hours after meeting him!"
Steve: "I can't even imagine how the last 5 years in prison was like for him..."
Megan: "His asshole is probably the 8th wonder in the world - almost as big as the Grand Canyon!"