I want to know about the origin of the compound adjective devil-may-care:
Cheerful and reckless:
light-hearted, devil-may-care young pilots
All OED has is
The exclamation devil may care! used as an attribute.
And etymonline.com says:
1837 (but suggested in other forms by 1793).
The earliest relevant result that I could find on Google Books was from 1823, and it was used there as an exclamation:
So where did this exclamation come from?