Green’s Dictionary of Slang

1. (Aus.) lit. or fig., malfunctioning, crippled.

1900		Sydney Sportsman (Surry Hills, NSW) 14 Nov. 1/3: Things must be ‘onky’ at brighton, when the show has to wait for one or two star punters [...] to return.
1937		Referee (Sydney) 6 May 21/5: Perfectly physically fit in other respects, he has an ‘onky'’ leg, and so he cannot race about as he would like to.

2. (Aus.) stinking, stale.

1948		Examiner (Launceston, Tas.) 5 Aug. 3/4: CRAYFISH WERE ‘ONKY’ Witnesses [...] gave various descriptions of the condition of the crustaceans [...] One said they were ‘onky,’ another said they were ‘stinking,’ still another said they were ‘very hot,’ and a fourth said they were ‘on the nose’.
1953		Baker Aus. Speaks.