in·sou·ci·ant (ĭn-ssē-ənt, ăɴ′s-syäɴ)
Marked by blithe unconcern; nonchalant.
[French : in-, not (from Old French; see IN-1) + souciant, present participle of soucier, to trouble (from Old French, from Vulgar Latin *sollicītāre, alteration of Latin sollicitāre, to vex; see SOLICIT).]
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