Synonyms for Irregular:

adj.

abnormal (adjective)
Anomalistic, funny, uncommon, spastic, bizarre, preternatural, peculiar, curious.
all (adjective)
unpredictable.
amorphous (adjective)
formless, shapeless, inchoate.
anomalous (adjective)
incongruous, untypical, inconsistent, abnormal.
asymmetrical (adjective)
unsymmetrical.
casual (adjective)
impulsive.
changeable (adjective)
flighty, inconstant, unsteady.
chaotic (adjective)
cluttered, out of control, obscure, chaotic, disconnected, confused, formless, tempestuous, embroiled, rambunctious, messy, inexact, undisciplined, disorganized, lawless, deformed, amorphous, blurry, inchoate, insane, anarchical, fuzzy, jumbled, lax, disarrayed, discomposed, shapeless, loose, deranged, indistinct, disorderly, indefinite, wild, disheveled, uneven, incoherent, perturbed, tumultuous, disordered, inconsistent, frenzied, anarchistic, Disintegrated, unruly, muddled, frantic.
crooked (adjective)
meandering.
deformed (adjective)
contorted, flawed, cockeyed, misshapen, bent, lopsided, disfigured, awry, crooked, corrupt, perverse, distorted, deformed, freakish, asymmetrical.
different (adjective)
unusual.
ghostly (adjective)
preternatural.
irregular (adjective)
haphazard, crooked, unequal, lopsided, cockeyed, bent, unsteady, fitful, elliptical, unsettled, fluctuating, lumpy, craggy, deviant, unmethodical, unsystematic, exceptional, divergent, strange, changeable, broken, casual, intermittent, notched, meandering, jagged, discontinuous, extraordinary, anomalous, recurrent, unconventional, improper, unreliable, unusual, infrequent, atypical, spasmodic, asymmetrical, fragmentary, unorthodox, uncertain, disorderly, unsymmetrical, unique, disconnected, odd, erratic, devious, eccentric, singular, jerky, amorphous, unrhythmical, wobbly, quirky, capricious, unnatural, desultory, occasional, different, variable, aberrant, sporadic, inconstant, hilly, uneven, asymmetric.
lumpy (adjective)
lumpy.
motiveless (adjective)
capricious, arbitrary, whimsical, sporadic, nonsystematic, flighty, careless, indecisive, fickle, Systemless, volatile, fanciful, wayward, reasonless, ambivalent, motiveless, impulsive, haphazard, unmethodical, adrift, random, rambling, spastic, wandering, chancy, Flitting, fleeting.
nonconforming (adjective)
crazy, uncustomary, outlandish, bizarre, different, crosspatch, fey, strange, extraordinary, quirky, oddity, misfit, unconventional, exceptional, novel, curious, aberrant, atypical, improper, mismatch, abnormal, idiosyncratic, nonconforming, odd, deranged, deviant, singular, oddball, un-ordinary, inconsistent, erratic, incongruous, untypical, divergent, unfamiliar, incompatible, peculiar, uncommon, eccentric, unusual, funny, anomalous, out of the ordinary, unique, off, freakish.
rough (adjective)
bumpy.

n.

airwoman, gi, crew, commando, grenadier, unnatural, foot soldier, green beret, bombardier, airman, cannon fodder. bumpy, lumpy, askew, winding, inclined, unsymmetrical, elliptical, hilly, meandering, craggy, unequal, notched, imperfect, damaged, jagged, wobbly, slanted, off balance, devious, at an angle, broken. Bedwetting, constipated, Egestion, evacuate, bowel movement, dry, constipation, bursting. compound, conditional, feminine, inflected, Frequentative, grammatical, declarative, deictic, complex. artifact (noun)
second.
irregular (noun)
randomised, randomized, unorthodox, strong, maverick, guerrilla, insurgent, asymmetrical, underground, substandard, occasional, casual, abnormal, partisan, unconventional, unlawful, arrhythmic, partizan, jerking, crooked, part-time, second, unsteady, atypical, guerilla, improper, uneven, grab, sporadic, unpredictable, temporary, jerky.
questionable (noun)
dubious, suspicious, questionable.

Other synonyms:

changeable, notched, Anomalistic, askew, unnatural, Atypic, slanted. grammatical, much, frequency, questionable, suspicious, irregularity. basis, rate, length. inclined. time. long. bumpy
hilly.
discontinuous
broken.
knotty
lumpy.
one-sided
unequal.
serrated
jagged.
spasmodic
discontinuous.
unlawful
unlawful.

Usage examples for irregular

  1. Far beyond the valley sharp summits and irregular ridges printed their bold outlines on the sky. – See America First by Orville O. Hiestand
  2. " Well, of course I could," he said, " though it would be rather irregular – Half-Past Bedtime by H. H. Bashford