The easiest way to summarize and define hardcore club hip-hop rap music: "Nigga-This-Fuck-That Music" as in, you will likely hear those phrases in this music. Contrast with pop / top 100 "dance music" like you typically get from Akon, Lady Gaga, Katy Perry, etc.
||| Bar DJ plays "Poker Face"... |||
Dancin' babe: "Can you play Little Wayne, "Always Strapped"?
Babe: Why not?
DJ: This is a bar, it isn't a club.
Babe: But you just played Gaga, it's the same thing!
DJ: No, it isn't. One plays anywhere, the other is NTFT music, we don't play that here.