ADJECTIVE (3)

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

2. varying from or not adhering to a standard;
- Example: "nonstandard windows"
- Example: "envelopes of nonstandard sizes"
- Example: "nonstandard lengths of board"

3. not standard; not accepted as a model of excellence;
- Example: "a nonstandard text"

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]

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]