modified
needless, causeless, fortuitous, casual, chance, haphazard, wanton, accidental, unessential, nonessential, beside the point, irrelevant, futile, extraneous, additional, redundant, useless, exorbitant, superfluous, worthless, undesirable, optional, avoidable, objectionable, disadvantageous, noncompulsory, random, dispensable, adventitious, without compulsion, uncalled for, pleonastic, gratuitous.
Antonyms necessary*, essential, required.