1
general::
1. It's not important, who cares, as in It cost a lot more, but what the hell, we can afford it. [Second half of 1800s] Also see WHAT OF IT. 2. An intensive of what, as in What the hell do you think you're doing? [First half of 1800s] Also see under ON EARTH.
American Heritage Idioms
2
general::
Phrase(s): What the hell?
Go to What the devil?, Phrase(s): What (in) the hell?
1. Inf. What has happened?; What? • What in the hell? Who did this? • What the hell happened here? 2. Inf. What does it matter? Why not? (Usually with the force of an exclamation.) • Give her a new one. What the hell! • Don’t be such a cheapskate. Get the nice one. What the hell!
McGrawhill's American Idioms And Phrasal Verbs