Synonyms of the word 
INSOUCIANCE → BLITHENESS - CAREFREENESS - CHEERFULNESS - LIGHTHEARTEDNESS - LIGHTSOMENESS
insouciance
- n. carelessness, heedlessness, indifference, or casual unconcern.
- n. nonchalance.
blitheness
- n. The characteristic of being blithe.
carefreeness
- n. The property of being lighthearted, joyous, cheerful, without a care.
cheerfulness
- n. The state of being cheerful; joy.
lightheartedness
- n. (uncountable) The property of being lighthearted, joyous, cheerful, without a care.
- n. (countable) An amusement or item of a pleasant but inconsequential nature.
lightsomeness
- n. (archaic) The quality of being lightsome.
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