Bitter verbal attack (8)
I believe the answer is:
diatribe
'bitter verbal attack' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for diatribe that I've seen before include "slating" , "A prolonged piece of invective" , "Vehement criticism" , "A Prolonged harangue" , "Torrent of abuse" .)