Green’s Dictionary of Slang

grouse adj.

also grouce
[ety. unknown; ? UK dial. crouse, happy, lively, pleased]

(Aus./N.Z.) wonderful, attractive, excellent, an all-purpose term of approval; also ironic use.

[Aus]G.H. Lawson Dict. of Aus. Words And Terms 🌐 GROUSE—Something good.
[Aus]L. Glassop We Were the Rats 5: You know them two grouse sheilas we’ve got the meet on with tomorer night?
[Aus]T.A.G. Hungerford Riverslake 74: Yeah, that’ll be grouse.
[Aus]B. Humphries Barry McKenzie [comic strip] in Complete Barry McKenzie (1988) 20: We used to have some extra grouse sing songs [...] back in Oz.
[Aus]J. McNeil How Does Your Garden Grow Act III: Grouse, mate. Grouse!
[Aus]R. Aven-Bray Ridgey-Didge Oz Jack Lang 14: The tucker was as grouse as it looked. He finished the meal and again took in his surrounds.
[Aus]R.G. Barrett You Wouldn’t Be Dead for Quids (1989) 63: You sure got a grouse view from out here.
[Aus]J. Byrell Lairs, Urgers & Coat-Tuggers xvii: before Orm Bunter was a regular customer at late and lairy nightclubs like the Roosevelt and Chequers where he paraded some grouse-class charlies.
[NZ]D. Looser ‘Boob Jargon’ in NZEJ 13 32: grouse adj. Excellent, of high quality, awesome - ‘good shit’.
[Aus]T. Winton ‘Immunity’ in Turning (2005) 294: Geez, I said. Sounds grouse.
[Aus]L. Redhead Peepshow [ebook] Honey’s grouse for stripper. Not stuck up or nothing.
[Aus]L. Redhead Thrill City [ebook] Candy [...] Grouse ta meet ya.

In compounds

grouse oil (n.)

(Aus.) reliable information, esp. in context of betting .

[Aus]J. Byrell Lairs, Urgers & Coat-Tuggers 101: Uncle Ern - a desperate in his salad days when it came to ‘the grouse oil’ and ‘lay-down misère certainties’.

In phrases

go for the grouse (v.)

(Aus.) to look for whatever is seen as worthwhile.

[UK]Partridge DSUE (8th edn) 508/1: later C.20.