Green’s Dictionary of Slang

wouldn’t that jar you phr.

(Aus./US) phr. of shock.

1911		‘Sing Sing No. 57,700’ My View on Books in N.Y. Times Mag. 21 May 7/4: There’s a bird in here by the name of Cigarette. Wouldn’t that jar you, Mabel?
1933		C. Drew ‘Gorilla Grogan’ in Bulletin (Sydney) 26 July 41/2: ‘I thought you tumbled. You did me a good turn oncest and I ain’t forgot it.’ Now, wouldn’t that jar you?