Irregular and Ill-formed

Irregular adjective - Departing from some accepted standard of what is normal.

Ill-formed and irregular are semantically related In some cases you can use "Ill-formed" instead an adjective "Irregular".

Nearby Words: irregularity, irregularly

Ill-formed adjective - Not grammatical; not conforming to the rules of grammar or accepted usage.

Irregular and ill-formed are semantically related in shapely topic. You can use "Irregular" instead an adjective phrase "Ill-formed", if it concerns topics such as formless, shapeless.