Green’s Dictionary of Slang

1. (orig. US) fair, honest, straightforward.

1882		Nat. Police Gaz. (NY) 11 Feb. 11/1: The fight was ‘up-and-up’ and Ryan won on his merits.
1928		Phila. Eve. Bulletin 5 Oct. 40/5: Here are a few more terms and definitions from the ‘Racket’ vocabulary: [...] ‘Up-and-up,’ honest.
1929		W.R. Burnett Little Caesar (1932) 10: It’s an up and up place. One of Francis Wood’s joints.
1949		Monteleone Criminal Sl. (rev. edn).
1952		(con. 1919) G. Fowler Schnozzola 29: On account of your brother, an up-and-up cop, I’m not going to pinch you this time.
1962		Ragen & Finston World’s Toughest Prison 822: up and up – [...] to be trusted.
1970		E. Thompson Garden of Sand (1981) 483: We’re an up and up place. The citizens know we’re here and consider us a public service.

2. (US) of individuals, events or objects, high-class.

1882		Nat. Police Gaz. (NY) 18 Feb. 11/3: George Davis had wooed and won the daughter of Maggie Myers, the richest colored woman in town. There was to have been an ‘up and up’ wedding .
1882		Nat. Police Gaz. (NY) 4 Mar. 7/4: [S]he could easily get another ‘feller’ from among the many who wanted her. For his part, he was going for a fine ‘up and up’ Chicago girl.

3. (Aus.) evenly matched.

1902

Bulletin (Sydney) 25 Oct. 26/3: Once M’Kell looked the better, then King appeared to have the advantage, and, later, it was ‘up and up,’ with the crowd marvelling at the vigor of the struggle and the stamina of the fighters. [...] [W]hen the 15th round opened referee ‘Don’ M’Donald stopped the fight and gave M’Kell the splosh.