Synonyms of irresponsible

1 Syllable

lax, rash, maer, wild

2 Syllables

fickle, loose, silly, sillier, skittish, ditzy, loco, ungrown, thoughtless, flighty, giddy, moonstruck, shiftless, slapdash, dippy, silliest, feckless

3 Syllables

immoral, no-account, birdbrained, unstable, unliable, insane, capricious, imprudent, foolhardy, puerile, ill-judged, incautious, derelict, immune, judgmental, fly-by-night, carefree, moronic, free-minded, careless, changeable

4 Syllables

reversible, untrustworthy, schizophrenic, unreliable, muddleheaded, agitable, overhasty, babylike, alarmable, immature, revocable, permutable, devil-may-care, harebrained, harum-scarum, uncareful, arbitrary, scatterbrained

5 Syllables

unaccountable, unanswerable, unpredictable, ill-considered, commutative, undependable, unadvisable, happy-go-lucky, pococurante