irregularity vs irregular

irregularity and irregular both are nouns.

Word	Noun	Adjective	Verb	Adverb
irregularity	Yes	No	No	No
irregular	Yes	Yes	No	No

irregularity (noun)	irregular (noun)
behavior that breaches the rule or etiquette or custom or morality	merchandise that has imperfections; usually sold at a reduced price without the brand name
not characterized by a fixed principle or rate; at irregular intervals	a member of an irregular armed force that fights a stronger force by sabotage and harassment
an irregular asymmetry in shape; an irregular spatial pattern
irregular and infrequent or difficult evacuation of the bowels; can be a symptom of intestinal obstruction or diverticulitis

irregularity (adjective)	irregular (adjective)
	contrary to rule or accepted order or general practice
	(of solids) not having clear dimensions that can be measured; volume must be determined with the principle of liquid displacement
	(used of the military) not belonging to or engaged in by regular army forces
	deviating from normal expectations; somewhat odd, strange, or abnormal
	failing to meet a standard of manufacture due to an imperfection
	lacking continuity or regularity
	not occurring at a regular rate or fixed intervals
	independent in behavior or thought
	(of a surface or shape); not level or flat or symmetrical