Definition of "Irregular" :

noun: merchandise that has imperfections; usually sold at a reduced price without the brand name

noun: a member of an irregular armed force that fights a stronger force by sabotage and harassment

adjective: not occurring at a regular rate or fixed intervals

"An irregular heartbeat."

adjective: independent in behavior or thought

"She led a somewhat irregular private life."

adjective: (of a surface or shape); not level or flat or symmetrical

"Walking was difficult on the irregular cobblestoned surface."

adjective: lacking continuity or regularity

"An irregular worker."

adjective: deviating from normal expectations; somewhat odd, strange, or abnormal

"Highly irregular behavior."

adjective: failing to meet a standard of manufacture due to an imperfection

"An irregular pair of jeans."

adjective: contrary to rule or accepted order or general practice

"Irregular hiring practices."

adjective: (of solids) not having clear dimensions that can be measured; volume must be determined with the principle of liquid displacement

adjective: (used of the military) not belonging to or engaged in by regular army forces

"Irregular troops."