Thesaurus

aberrant, abnormal, abrasive, aflicker, agitated, alligatored, amerciable, anomalous, antidromic, arrhythmic, arrhythmical, asymmetric, asymmetrical, atypical, banned, barky, black, black-market, bohemian, bootleg, bouldered, bouldery, brachydactylic, brachydactylous, broken, bullate, bumpy, casual, chapped, coarse, coarse-textured, contraband, convulsive, corded, costate, cracked, cragged, craggy, criminal, crinkled, crinkly, crooked, cross-grained, crushed, curly-grained, defective, deviant, deviate, dirty, discontinuous, disorganised, disorganized, embezzled, extrajudicial, extralegal, faltering, felonious, fitful, flickering, fluctuating, freakish, go-as-you-please, half-time, harsh, hilly, homespun, hot, ill-gotten, illegal, illegitimate, illicit, imbricate, imbricated, improper, ineligible, infrequent, insane, intermittent, irregular, isolated, jagged, jaggy, jerking, jerky, kinky, lepidote, leprose, lined, lopsided, lumpy, maverick, misappropriated, misbranded, mislabeled, mountainous, noncontinuous, noninterchangeable, nonlegal, nonrhythmic, nonslippery, nubbly, nubby, occasional, odd-job, original, out of true, outlaw, outlawed, palpitant, palpitating, part-time, partisan, partizan, parttime, patchy, pebble-grained, penal, periodic, perverted, pocked, pockmarked, potholed, prohibited, punishable, quavering, ragged, randomised, randomized, ribbed, rippled, rocky, rough, rough-textured, roughened, roughish, rugged, rugose, sandpapery, saw-like, scabby, scabrous, scaly, scraggy, scratchy, scurfy, seamed, shagged, shaggy, shaky, shifting, shifty, shivering, shuddering, slubbed, smuggled, spasmodic, spastic, sporadic, squamulose, stony, stray, strong, subnormal, supernormal, temporary, textured, tottering, tottery, trembling, tremulous, tweedy, twilled, unconventional, under-the-counter, underemployed, uneven, unironed, unlawful, unorthodox, unparallel, unpolished, unpredictable, unratified, unrhythmic, unrhythmical, unsmooth, unstable, unsteady, unsymmetric, unsymmetrical, unsystematic, unsystematised, unsystematized, untrue, verrucose, vicarious, wartlike, warty, wavelike, wavy, wavy-grained, wobbling, wrinkled

irregular is a ADJ.

guerilla, guerrilla, insurgent, irregular, second

irregular is a NOUN.