In a violent frenzy (7)
I believe the answer is:
berserk
'in a violent frenzy' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for berserk that I've seen before include "(Go) wildly destructive" , "Frantic" , "nuts" , "In a violent frenzy" , "Wild, frenzied" .)