Seven Hells
A popular substitution for "bloody hell", "god dammit, or "motherfucker" used when faced with a particularly troublesome or preposterous obstacle. A reference to one of the curses in Game of Thrones. You can tell whoever uses this term probably needs to stop watching Game of Thrones and go outside more.
I told Joey that his girl slept with our chemistry professor and he responded "Seven Hells!". No wonder she slept around.