Green’s Dictionary of Slang

1. first-rate, excellent, enjoyable.

[1835		Worcester Herald 26 Dec. 4/3: chusty, good].
1865		Bristol Times 17 Oct. 4/1: Do you know any commister (clergyman) here? Yes there is one, he is a cushtie (good one).
1985		J. Sullivan ‘Sleeping Dogs Lie’ Only Fools and Horses [TV script] No, no no, no, everything’s cushty!
1989		J. Morton Lowspeak 46: Cushti – an exclamation of approval.
1998		K. Sampson Awaydays 98: Our goons want it all cushty with the management just like they always have done.
2000		Guardian Rev. 3 Nov. 17: Purely Belter means more brilliant than ‘cushdy’ or ‘mint’; it means, as it were, doubleplusgood.
2004		Dizzee Rascall ‘Knock, Knock’ 🎵 That’s cushty, mate, I’m gettin’ paid, more than you tonight.
2013		Esquire 1 Sept. 🌐 He was on a sales call about to land a cushty deal and nail a wad of commish.

2. on good terms, involved with sexually.

2000

N. Barlay Crumple Zone 139: Georgio already thinks you’re all cushty with Alv.

3. physically comfortable.

2000

N. Barlay Crumple Zone 196: Ah can see you’re all cushty an’ Ah’m aimin’ to leave you the way Ah found you.