1. not conforming to or meeting official standards, rules, or accepted norms
2. relating to language that does not follow accepted grammatical or usage rules
Usage: linguistics

Examples

• The company used nonstandard equipment that didn’t meet safety regulations.
• His nonstandard approach to the problem yielded surprising results.
• The teacher corrected the student’s nonstandard grammar.
• Double negatives are considered nonstandard in formal English.
• The building’s nonstandard dimensions made it difficult to find replacement parts.
• She spoke in a nonstandard dialect that was hard for outsiders to understand.