The Collaborative International Dictionary
non-U \non-U"\ (n[o^]n*[=u]"), adj. Not characteristic of the upper classes especially in language use. [Chiefly British] [Narrower terms: lower-class (vs. middle-class) (vs. upper-class), low-class]
adj. not characteristic of the upper classes especially in language use
Usage examples of "non-u".
Helen Steeply was taken by female prorector Thierry Poutrincourt, freshly showered, long-faced, a non-U.
I think it was something to do with working her way around the Solar System on a cut-price non-U grand tour: laboring as a courtesy masseuse in Japan and a topiarist on Ceres while saving up the price of her next interplanetary jaunt.