Green’s Dictionary of Slang

(Aus.) the odds-on favourite, in a horserace or other sporting contest.

1941

19501960

1970

1941		Baker Popular Dict. Aus. Sl. 50: An odds-on, an odds-on favourite.
1970		K. Mackey Cure 148: You’re the most unhappy man I’ve ever met since Odds-on Charlie when he backed eleven consecutive losers.