Green’s Dictionary of Slang

grizzly adj.

(UK juv.) infuriating, maddening.

[UK]A. Brazil Luckiest Girl in School 125: ‘Oh, the grizzly bad luck of it!’ she wailed to Garnet. ‘It would have been idyllic to coach those kids’ [ibid.] 126: ‘Did you ever hear of such grizzly luck in your life?’.