IRREG'ULAR, adjective [Latin irregularis; in and regularis, regula. See Regular.] 1. Not regular; not according to common form or rules; as an irregular building or fortification. 2. Not according to established principles or customs; deviating from usage; as the irregular proceedings of a legislative body. 3. Not conformable to nature or the usual operation of natural laws; as an irregular action of the heart and arteries. 4. Not according to the rules of art; immethodical; as irregular verse; an irregular discourse. 5. Not in conformity to laws, human or divine; deviating from the rules of moral rectitude; vicious; as irregular conduct or propensities. 6. Not straight; as an irregular line or course. 7. Not uniform; as irregular motion. 8. In grammar, an irregular noun or verb is one which deviates from the common rules in its inflections. IRREG'ULAR, noun A soldier not in regular service.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI