not conforming to the language usage of a prestige group within a community; a nonstandard dialect is one used by uneducated speakers or socially disfavored groups; the common core of nonstandard words and phrases in folk speech- A.R.Dunlap

varying from or not adhering to a standard; nonstandard windows; envelopes of nonstandard sizes; nonstandard lengths of board'

not standard; not accepted as a model of excellence; a nonstandard text'