unconcernEnglishOxford English Thesaurusunconcern noun I affected a supreme unconcern: indifference, apathy, lack of concern, lack of interest, uninterestedness, nonchalance, equanimity, insouciance, lack of involvement, passivity, dispassionateness, dispassion, detachment, aloofness, remoteness, reserve. ▷antonyms concern, commitment.unconcern Oxford Dictionary of English