nonstandard

adjective

1. not conforming to the language usage of a prestige group within a community

   adj.all

   Examples

   A nonstandard dialect is one used by uneducated speakers or socially disfavored groups.

   The common core of nonstandard words and phrases in folk speech.

   Antonyms received standard

   Source: WordNet 3.0

2. varying from or not adhering to a standard

   adj.all

   Examples

   Nonstandard windows.

   Envelopes of nonstandard sizes.

   Nonstandard lengths of board.

   Source: WordNet 3.0

3. not standard; not accepted as a model of excellence

   adj.all

   Examples

   A nonstandard text.

   Antonyms standard

   Source: WordNet 3.0