in·sou·ciant \-sēənt, -shənt, F -syäⁿ\adjective Etymology: French, from in- in- (I) + souciant, present participle of soucier : exhibiting or characterized by insouciance < an insouciant manner > < a gay insouciant person > • in·sou·ciant·ly\-sēəntlē, -shən-, -li\adverb