insouciant
1. [ adjective ] marked by blithe unconcern
Synonyms: casual nonchalant
Examples:

"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"

Related terms: unconcerned
Similar spelling:   insouciance
  incognizant