Never thought I'd need to check a dictionary for something like that, but what the hell:
From dictionary.com:
adjective, edgier, edgiest.
1. nervously irritable; impatient and anxious.
2. sharp-edged; sharply defined, as outlines.
3. daringly innovative; on the cutting edge.
I thought we had this conversation already... It's not our world they are living in, so our definition of the word "hero" obviously doesn't apply. It's an official word in that world with plenty of hero academies and media coverage.