Definition from Wiktionary, the free dictionary
See also: nonu
non-U (not comparable)
- (chiefly Britain) not U; not characteristic of the upper classes, particularly regarding language.
- 1992, John Algeo, “Sociolinguistic Attitudes and Issues in Contemporary Britain,” in English in Its Social Contexts, Tim W Machan and Charles T Scott edd. 
- The concept of U (for upper-class British usage, as opposed to non-U, or everything else) was introduced by Alan S. C. Ross (1954) and was taken up by Nancy Mitford (1956), becoming for a time something of a parlor game in which the participants tested themselves and everyone else for signs of U and non-U status.
- 2001, Stephan Gramley, The Vocabulary of World English 
- For this we must turn to speculations such as those offered in connection with U and non-U English.
- 2003, Philip Pettit, Rules, Reasons, and Norms 
- To speak of lavatories is U, of bathrooms non-U; to lay cloth napkins at table is U, to lay paper napkins non-U; and so on through a myriad of equally trivial examples.
- 1992, John Algeo, “Sociolinguistic Attitudes and Issues in Contemporary Britain,” in English in Its Social Contexts, Tim W Machan and Charles T Scott edd.