Used to describe a person who is the best in their respective field. And commonly used by people who know they're not the best but need to say it to clarify that they are not the worst.
Can be used to classify a person, or it can be used to describe a persons pro-like actions.
>99%, undefeated, untouched, invincible, the best, your mom wishes I was her only child, etc. What can I say? I'm all of these things. I'm hella pro.
EX 1:
Tom: Did you study for that test today?
Sam: Nah, dude. I'm hella fucked...
EX 2:
Jim: The Yanks have 3 on and none out.
Tim: Yeah, the BoSox are hella fucked, yo...
EX 3:
Eric: Dude, I just got caught with an ounce o'diesal on me.
Swin: HAHA..yer hella fucked, yo...