Billy J. His name alone tells you he is, was, and always will be one of the realest motherfuckers there ever was. Billy the realest motherfucker who everwas,gives nofucks about motherfucker who wasn't. He has been said to have told Chuck Noris to his face he looked like a fake motherfucker and walked away unscathed.
An individual who can always see through the bullshit. Particular people who don't like sugar coating or pussyfooting and/or beating around the bush. A person who takes their own inventory before taking anyone else's.
Male RMF: a proud solid man, one whom has the most sensitive bullshitometer.
Female RMF: a bitch who is down to go ham on yo girl when she acting a hoe round her mans.
Remember how that dude Barret always was genuine and his own brand, that dude was a RMF (Real Mother Fucker)
when you're holding up your phone and making faces at it, as though you are taking a selfie, but you're really taking a picture of the person across from you or the wall or anything else that seems interesting but you don't want to be caught dead taking a picture of.
This action is often made more convincing by wiggling the eyebrows or opening the mouth, to pretend you're trying to get a Snapchat filter to work.
FRIEND A: "Did you just take a stealthie of me?"
FRIEND B (turning phone around): "no I was just using snapchat's new filter, see?"