Green’s Dictionary of Slang

(Aus.) genuine, honest.

1953		I. Bevan Sunburnt Country 130: Ridgy Didge [...] means the truth.
1953		K. Tennant Joyful Condemned 294: He’d tell you himself I’m ridgey-dite. I worked for him.
1963		(con. 1944) L. Glassop Rats in New Guinea 153: ‘Are you serious [...] Surely you’re making it up?’ ‘It’s ridgie-didgie,’ said Eddie. ‘Spit me death.’.
1968		S. Gore Holy Smoke 65: ‘Yes. Ridgey-the-didge, mate,’ said Jesus.
1979		D. Maitland Breaking Out 302: I just don’t like taking shit from bloody lawyers [...] that’s all. Fair dinkum. Ridgy-didge.
1986		R. Beckett Dinkum Aussie Dict. 44: Ridgie didge: On the level; the good oil. The truth.
1999		Guardian G2 1 Nov. 3: She would like to see a president who is ‘a full ridgy-didge Aussie bloke’.
1999		G. Seal Lingo 91: ridgy-didge is an expression of approval, signifying that something is genuine. The related ridgy-dite means all right and is used to indicate that someone or something is genuine, to be trusted.
2016		N. Cummins Adventures of the Honey Badger [ebook] Over the next two weeks we would come to know him as a dead-set, ridgy-didge champion.