accidental

1 happening by chance finding the gold was all the more remarkable because its discovery was entirely accidental Synonyms casual, chance, fluky (also flukey), fortuitous, inadvertent, incidental, unintended, unintentional, unplanned, unpremeditated, unwitting Related Words coincidental; freak, odd; aimless, arbitrary, desultory, haphazard, random; uncertain, unexpected, unforeseeable, unforeseen; coerced, forced, involuntary; unconscious, unprompted Near Antonyms certain, destined, expected, fixed, foreordained, foreseeable, foreseen, inevitable, predestined, predetermined, predictable, preordained, prescribed, sure; conscious, freewill, knowing, unforced, voluntary, volunteer, willful (or wilful) Antonyms calculated, deliberate, intended, intentional, planned, premeditated, premeditative, prepense, set

2 not being a vital part of or belonging to something we're considering the painting's merit as a work of art, its commercial value being entirely accidental as far as we're concerned Synonyms extrinsic, adventitious, alien, extraneous, external, foreign, supervenientRelated Words exterior, outside; immaterial, inapplicable, insignificant, irrelevant; nonessential, unessential, unnecessaryNear Antonyms congenital, deep-seated, inborn, inbred; inside, interior, internal; basic, essential, necessaryAntonyms inherent, innate, intrinsic