Green’s Dictionary of Slang

(Aus.) honest, genuine, trustworthy; note cit. 1939 transfers usage to a n.

1906		E. Dyson Fact’ry ’Ands 92: ’Twasn’t fair dink t’go outside ther firm.
1915		Sun. Times (Perth) 20 June 8/8: Cos us wot knoo ’im well / Seemed ter think ’e ’ad a spell / Wot ’ud git ’im out of ’ell, / Fair the dink.
1927		Ellesmere Guardian 27 May 4/3: ‘Fair the dink’, Square and above board.
1939		W.E. Mckinlay Ways and Byways of Singing Kiwi I 24: The sobriquet for the 3rd Brigade had many variants from the original ‘Dinks;’ one of the Battalions being known as the ‘Square Dinks’ and another as the ‘Fair Dinks’ .