Green’s Dictionary of Slang

(Aus. und.) in card-playing, a pack of marked cards [they tell the cheat the card’s value].

1895

Crowe Aus. Sl. Dict. 84: Tell Box, a marked pack of cards used by swindling gamblers.

(US black) to reprimand someone, to upbraid someone, to tell someone off.

1923

Alberta Hunter ‘Aggravatin’ Papa’ 🎵 Aggravating Papa, don’t try to two-time me! / Aggravatin’ Papa, treat me kind or let me be; / Listen while I get you told, / Stop messin’ round with my jellyroll, / If I catch you out with your high-brown baby, / I’ll smack you down, and I don’t mean maybe!

see also under relevant n.

(orig. US black/hippie) to be absolutely honest, to reject dissembling; often as an exhortatory imperative; also attrib.

1937		E. Freeman ‘The Whirling Hub’ in Afro-American (Baltimore, MD) 13 Apr. 15/3: [A] hair-pulling contest [when] Frances Curtis told it to Ollie Day with blows.
1941		A. Lomax Mister Jelly Roll (1952) 19: I guess I will have to tell it as it is.
1943		W. Guthrie Bound for Glory (1969) 265: You’ll get a feed [...] if you’re honest, willing to work for it, and ain’t afraid to tell it like it is.
1954		W.G. Smith South Street 170: ‘TELL ’EM ABOUT IT, BABY!’.
1963		W.G. Smith Stone Face 103: ‘Tell ’em ’bout it, Babe!’ Benson said. He held his hand across the table. ‘Gimme some skin, man. You right!’.
1967		F. Salas Tattoo the Wicked Cross (1981) 301: Now, tell-me-like-it-is, man? Is that revenge, man? Now, tell me, Aaron? Tell-me-like-it-is?
1967		P. Thomas Down These Mean Streets (1970) 125: ‘What you doing now, man, defendin’ the paddies?’ I asked. ‘Jus’ sayin’ like it is.’.
1971		H.E. Roberts Third Ear n.p.: tell it like it is, tell it like it be, tell it like it am v. to reveal all of the facts; to be frank and candid, letting the chips fall where they may.
1977		A. Brooke Last Toke 11: You know it, baby. You just keep on tellin’ it like it is.
1985		B. Humphries Traveller’s Tool 7: Publishers have been putting the hard word on me for yonks to spill the beans, tell it like it is and tip the bucket.
1999		Indep. on Sun. Rev. 5 Sept. 36: The prize for the most say-it-like-it-is menu in all of eatingdom.
1999		Observer Rev. 1 Aug. 16: So British, isn’t it, that business of never quite telling it like it is?
2006		C. Carr Our Town 216: Everybody claimed to be Klansmen then, [...] I’m gonna tell you like it is.

phr. of emphatiic, if dismissive agreement: ‘you think I don’t know?’.

1984		D. Jenkins Life Its Ownself 263: ‘You need help in the offensive line,’ I said. ‘Tell me about it,’ the coach said. ‘Powell there can’t spit over his chin’.
1996		W.D. Myers Slam! 2340: ‘Ice is good,’ Ducky said. ‘He can do anything.’ ‘Tell me about it,’ I said.

see know a thing or two v.