Green’s Dictionary of Slang

(US) genuine, telling the truth; also attrib.

a.1954		‘Mexicana Rose’ in D. Wepman et al. Life (1976) 38: Creep, are you for real?
1961		J. Kirkwood There Must Be a Pony! 1011: The for-real cop only took one quick glance.
1966		J. Mills Panic in Needle Park (1971) 67: She was regular people, like for real.
1972		Milner & Milner Black Players 198: Boss players are generally more gentle and ‘for real’ with their women.
1980		E. Folb Runnin’ Down Some Lines 20: Like you got your righteous kin — for real brothers and sisters.
1989		(con. 1950s–60s) in G. Tremlett Little Legs 100: The next time it will be for real.
1989–2003		R.O. Scott Gay Sl. Dict. 🌐 4-real: the person is not interested in superficial relationships, liars or exaggeration.
1996		J. Cameron It Was An Accident 40: You think them shooters are for real or is it you think that geezer nearest you is holding a water pistol?
1998		(con. 1986) G. Pelecanos Sweet Forever 88: Either death or jail awaits those boys on the for-real side.
2001		N. Barlay Hooky Gear 161: How come he just walk in my life an get handed a menu an information an make request for phone calls like he was a for real bruvver an all that.
2004		M.N. Ryan Man For the Job 174: ‘Is she for real?’ Marina gave Gwyneth a sad little smile. ‘I’m afraid so.’.
2006		Burns & Price ‘Corner Boys’ Wire ser. 4 ep. 8 [TV script] Somethin’ for real happen, you do that [i.e. beat someone up]. You do it over bullshit. All you do is lose the good work.
2013		K. Sampson Killing Pool 211: I genuinely believe he’s for real here.