Green’s Dictionary of Slang

real, the n.

[abbr. real thing, the n.]

the genuine article, esp. in the phr. what’s the real?, what’s going on? what’s the meaning?

[UK]Bell’s Life in London 23 Dec. 2/5: Jem Ward for a lusty tureen [...] order’d to give ’em four quarts of the real.
[UK]C.D.Warner Blacklog Studies 4: A cynic might suggest as the motto of modern life this simple legend – ‘Just as good as the real’ [F&H].
[US]D. Goines Street Players 48: That’s right, baby...the real will come out.

In phrases

on the real (adv.)

(US black teen) honestly, sincerely, truthfully.

[US]T.R. Houser Central Sl. 39: on the real [...] ‘I ain’t never carried no gun; on the real’.
[US]College Sl. Research Project (Cal. State Poly. Uni., Pomona) [Internet] On the real (phrase) For real, I’m telling you the truth, and let me tell you something.
[US]P. Beatty Tuff 181: On the real, though [...] We need a voice. One of us speaking.