Green’s Dictionary of Slang

aces adj.

[ace n. (3)]

1. (US) of both people and objects, wonderful, marvellous, excellent; thus you’re aces!

[US]‘Hugh McHugh’ Down the Line 96: Those musicale things would be aces if the music didn’t set them back.
[US]J. Lait ‘Omaha Slim’ in Beef, Iron and Wine (1917) 117: Your dope is all aces.
[US]Gleason & Taber Is Zat So? I i: chick: Gee, Hap, do you think it’s all right? hap: Aces, you sap!
[US]Cab Calloway ‘Copper Colored Gal’ [lyrics] Oh, gee, sweet as can be, / You’re aces with me, / I mean, aces high.
[US]R. Chandler High Window 143: ‘Oh, yes,’ she said. ‘Yes, indeed.’ Leslie was aces. With her.
[US]J.D. Salinger Catcher in the Rye (1958) 54: You’re aces, Ackley kid.
[US](con. WWII) J.O. Killens And Then We Heard The Thunder (1964) 427: She’s aces, mytes, and she’s full quid all the way.
[UK]N. Smith Gumshoe (1998) 59: I’m aces with crushing remarks.
[US]R. Price Breaks 240: You’re fuckin’ aces, kid!
[US]E. Weiner Drop Dead, My Lovely (2005) 24: ‘Boss? A Ms. Flonger to see you.’ ‘Aces, Miss Constantino. Show her in.’.

2. (US, also aces up) esteemed, well-respected, favoured.

[US]‘Hugh McHugh’ Out for the Coin 34: Murf [...] you’re aces up with me from this moment.
[US]H. Green Actors’ Boarding House (1906) 355: You, who used to be aces with all the chorus girls, too!
[US]J. Tully Bruiser 35: A gut who can tear Maley to pieces is aces up with me.
[US] ‘“Ace” and its Progeny’ in AS XVIII:1 Feb. 72/1: aces up. Excellent, pleasing.
[US]S. Morgan Homeboy 369: But I’m aces with the A.B. here.
[US]E. Bunker Mr Blue 60: Anybody’d nail that piece of shit is aces with me.

In phrases

aces and eights (adj.) [poss. misreading of the usual idea of bad luck in a hand of aces and eights (that supposedly held by Wild Bill Hickok when he was gunned down on 2 August 1876)]

wonderful, marvellous, excellent.

[US]Times (Richmond, VA) 17 Nov. 18/5: In this same Town there was a Boy who was Aces and Eights with the Girls.
Hope Pioneer (ND) 23 May 4/3: Danny Murphy has a boost for [...] T. Cobb [...] when it comes to the personal stuff it’s aces and eights for Tyrus.
[US]Ade Hand-made Fables 16: ‘Except for one Peculiarity, you think she’s all right?’ ‘Aces and eights!’.
[US]Wash. Times (DC) 1 Oct. 46/6: ‘The little Lady is not so Bad, is she?’ ‘Aces and Eights’.