irregular

(a) contrary to rule or accepted order or general practice
- irregular hiring practices
(s) not occurring at expected times unpredictable,
(a) (used of the military) not belonging to or engaged in by regular army forces
- irregular troops
- irregular warfare
(a) (of solids) not having clear dimensions that can be measured; volume must be determined with the principle of liquid displacement
(s) falling below the manufacturer's standard
- irregular jeans
(s) deviating from normal expectations; somewhat odd, strange, or abnormal
- these days large families are atypical
- atypical clinical findings
- atypical pneumonia
- highly irregular behavior
atypical,
(s) lacking continuity or regularity
- an irregular worker
- employed on a temporary basis
temporary,
(s) (of a surface or shape); not level or flat or symmetrical
- walking was difficult on the irregular cobblestoned surface
(s) independent in behavior or thought
- she led a somewhat irregular private life
- maverick politicians
maverick, unorthodox,

(n) a member of an irregular armed force that fights a stronger force by sabotage and harassment guerilla, guerrilla, insurgent,
(n) merchandise that has imperfections; usually sold at a reduced price without the brand name second,

guerilla guerrilla insurgent unpredictable second atypical temporary maverick unorthodox

regular

irregularity irregularly