insouciance n. + Add to list US //ˌɪnˈsusiəns// UK //ɪnsˈaʊʃiəns// in·sou·ciance SynonymsEtymology Synonyms carefreenesslightheartednesslightsomenessOriginFRAinsouciance→ENinsouciance From French insouciance, from in- (“not”) + souciant (“worrying”).