from The American Heritage® Dictionary of the English Language, 4th Edition
- adj. Marked by blithe unconcern; nonchalant.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. Carefree, nonchalant, indifferent; casually unconcerned.
from the GNU version of the Collaborative International Dictionary of English
- adj. Careless; heedless; indifferent; unconcerned.
from The Century Dictionary and Cyclopedia
- Destitute of care or forethought; heedless of consequences or of the future; indifferent; unconcerned.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- adj. marked by blithe unconcern
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).(American Heritage® Dictionary of the English Language, Fourth Edition)
From French insouciant from in- (“not”) + souciant (“worrying”) (Wiktionary)