without symmetry, even shape, formal arrangement, etc.: an irregular pattern.
not characterized by any fixed principle, method, continuity, or rate: irregular intervals.
not conforming to established rules, customs, etiquette, morality, etc.: highly irregular behavior.
not according to rule, or to the accepted principle, method, course, order, etc.
not conforming to the prevalent pattern or patterns of formation, inflection, construction, etc., of a language; having a rule descriptive of a very small number of items: The English verbs “keep” and “see” are irregular in their inflections.
(formerly, of troops) not belonging to an organized group of the established forces.
flawed, damaged, or failing to meet a specific standard of manufacture: a sale of irregular shirts.
not uniform.
(of a flower) having the members of some or all of its floral circles or whorls differing from one another in size or shape, or extent of union.
deviating or experiencing deviations from a normally regular or cyclic body function, as bowel habits or menstruation.
(of a stock or commodity market) of mixed market activity; showing no clear up or down trend.
—n.
a person or thing that is irregular.
a product or material that does not meet specifications or standards of the manufacturer, as one having imperfections in its pattern.
a soldier or combatant not of a regular military force, as a guerrilla or partisan.