marked by blithe unconcern
I read this word in a blog this week (sorry, I don’t remember which one!). Here’s a sentence for it:
Jessi Gage was the oposite of incousiant when her laptop stopped charging last week and she had to wait an enire week for a new battery and charger.
Definition from http://www.onelook.com/?w=Insouciant+&ls=a