Green’s Dictionary of Slang

gay and hearty n.

(Aus.) a party.

1912		Sport (Adelaide) 3 Aug. 14/3: They Say [...] That Shorty and Squire were at a local gay and hearty [...] and went home sober.
1913		Sport (Adelaide) 26 July 10/2: Jeanie C. and Myrtle W. were the pick of the basket at the ‘gay and hearty’ Tuesday night.
1939		K. Tennant Foveaux 176: She’ll be with a gay, not just a bunny anyone would pick up.
1967		‘Whisper All Aussie Dict.’ in Kings Cross Whisper (Sydney) xxxv 6/1: gay: A [...] party from rhyming slang, gay and hearty.
1972		Dodson & Saczek Dict. of Cockney Rhy. Sl.
1983		J. Byrell (con. 1959) Up the Cross 37: They even had a celebration gay ’n’ hearty.
1983		R. Aven-Bray Ridgey-Didge Oz Jack Lang 29: Gay and Hearty Party.
1996		J. Byrell Lairs, Urgers & Coat-Tuggers 100: Uncle Ern [...] invites the still wet and all but whiskerless youth over to his Five Dock 76th gay’n’hearty.
1998		R. Puxley Fresh Rabbit.
2002		Pete’s Aussie Sl. Home Page 🌐 gay and hearty: a party.