Douglas Harper's Etymology Dictionary
un-English
"lacking in qualities regarded as typically English," 1630s, from un- (1) "not" + English (adj.).
Usage examples of "un-english".
Her clothes were country-made, but perfect as regarded fit and trimness, her beflowered hat was worn with a touch of coquettish grace, a trifle un-English, but very delightful.
I became conscious that I was on un-English ground at Gobowen, a Welsh junctional point where the ticket-taker thanked me in the Welsh form -- "ddiolch yn fawr.