Raven generally has to retaliate (6)
I believe the answer is:
avenge
'to retaliate' is the definition.
('avenge' can be a synonym of 'retaliate')
'raven generally has' is the wordplay.
'has' says the answer is hidden in the clue.
'AVENGE' can be found hidden inside 'raven generally'.
(Other definitions for avenge that I've seen before include "Redress, vindicate" , "Dish out a dose of own medicine" , "Retaliate on behalf of" , "Exact retribution on behalf of (someone)" , "Exact retribution, take satisfaction for injury" .)