noun-modifying (irregular)
free-form; unconventional
Used for creative works that do not follow a fixed pattern, especially poetry or verse.
He likes writing free-verse poetry.
noun-modifying (irregular)
atypical; non-standard
General term for something that does not fit a typical pattern or standard; used in technical or descriptive contexts.
This condition can sometimes follow an atypical course.
atypical pneumonia
atypical psychosis
Compound of 非 (hi, 'non-') and 定型 (teikei, 'fixed form').