Definitions for nonstandard

(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")