Green’s Dictionary of Slang

cheek, impudence, malicious gossip.

1901		letter in C. Pettman Africanderisms (1913) 42: ‘That’ll do, Sargeant Jones,’ I heard one of our colonial officers remark, ‘I don’t want any more of your back-chat.’.
1912		Bulletin (Sydney) 19 Dec. 16/1: There are many Maori proverbs which have not yet seen the light of print. Some of Henare’s sayings are very subtle, and, in some cases are synonymous with the shearer’s ‘backchat.’.
1915		C.J. Dennis ‘The Intro’ in Songs of a Sentimental Bloke 19: But strike! The way she piled on dawg! Yer’d think / A bloke was givin’ backchat to the Queen.
1925		M. Arlen May Fair (1947) 254: His Highness [...] was so agreeably affected by the swift interchange of repartee and back-chat.
1930		E. Waugh Vile Bodies 100: Back-chat again [...] Girls, I’m sick ashamed of you.
1936		W. Holtby South Riding (1988) 50: Pleased by opportunities for flirtatious back-chat.
1945		‘Henry Green’ Loving (1978) 145: We don’t want none o’ your backchat my gel thank you.
1958		A. Sillitoe Sat. Night and Sun. Morning 33: [He] took backchat with a wry smile and a good face.
1961		‘Frank Richards’ Billy Bunter at Butlins 36: Troubles in Central Africa, and the latest back-chat from Moscow, were merely a drone in his ears.
1974		D. Ireland Burn 127: You’re comin’ with me and don’t let’s hear any backchat out of ya.
1985		C. Achebe African Short Stories 111: I don’t want any back-chat.
1994		M. Montague Dread Culture 21: Listen, gal pickney, nuh give me no backchat.
2000		Indep. Rev. 7 Feb. 8: Joe became more argumentative. She had more backchat and was always in a mood.
2008		New Yorker LVIIIIV 149: The jovial, cultivated Ken squares off against his more impatient sidekick, and their backchat hits an appealing rhythm.