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