nonstandard

from WordNet (r) 3.0 (2006)

nonstandard
    adj 1: 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 [ant: {received}, {standard}]
    2: varying from or not adhering to a standard; "nonstandard
       windows"; "envelopes of nonstandard sizes"; "nonstandard
       lengths of board" [ant: {standard}]
    3: not standard; not accepted as a model of excellence; "a
       nonstandard text" [ant: {standard}]

from The Collaborative International Dictionary of English v.0.48

nonstandard \nonstandard\, non-standard \non-standard\adj.
   1. varying from or not adhering to a standard; as,
      nonstandard windows; envelopes of nonstandard sizes;
      non-standard lengths of board cost more per foot. Opposite
      of {standard}. [Narrower terms: {deficient, inferior,
      substandard}]

   Syn: nonstandard.
        [WordNet 1.5]

   2. (Linguistics) Not conforming to the language usage of a
      prestige group within a community; as, a nonstandard
      dialect is one used by uneducated speakers or socially
      disfavored groups. Opposite of {standard}.
      [WordNet 1.5]