Green’s Dictionary of Slang

white adv.

[white adj. (2)]

honestly, fairly; usu. in comb. with treat.

[US]H.O. Flipper Colored Cadet at West Point 54: ‘To be white,’ ‘To treat white.’ — To be polite, courteous, and gentlemanly.
[Aus]Worker (Brisbane) 4 Sept. 8/3: A pound a hundred, ‘in or out,’ with rules and tucker fair, / He designates as ‘working white’ and shearing ‘on the square’.
[US]C.L. Cullen Tales of the Ex-Tanks 20: Never got handled so white in my life.
[US]C. M’Govern By Bolo and Krag 50: Well, sir, they treated us white did them gu-gus.
[Aus]Bulletin (Sydney) 12 Dec. 42/3: D’yer think I’d go givin’ it erway like that arter yer treatin’ me white like y’ve done?
[US]‘Max Brand’ Pleasant Jim 304: You’ve played so white with me.
[US]J. Conroy Disinherited 183: Some o’ you crummy bastards don’t appreciate it when a man aims t’ treat ya white.
[US]R. Price Ladies’ Man (1985) 93: Everybody was treating me white.