insouciance
— Noun
– English
~ the cheerful feeling you have when nothing is troubling you
insouciant
— Adjective
– English
~ marked by blithe unconcern; "an ability to interest casual students"; "showed a casual disregard for cold weather"; "an utterly insouciant financial policy"; "an elegantly insouciant manner"; "drove his car with nonchalant abandon"; "was polite in a teasing nonchalant manner"