Definition of non-standard
1. nonstandard [ a ] varying from or not adhering to a standard
Examples: "nonstandard windows" "envelopes of nonstandard sizes" "nonstandard lengths of board"
2. nonstandard [ a ] (linguistics) not conforming to the language usage of a prestige group within a community
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"- Dunlap
3. nonstandard [ a ] not standard; not accepted as a model of excellence
Examples: "a nonstandard text"