Group expressing anger to some extent (4)
I believe the answer is:
gang
'group' is the definition.
(gang is a kind of group)
'expressing anger to some extent' is the wordplay.
'to some extent' indicates a hidden word.
'GANG' is hidden within 'expressing anger'.
(Other definitions for gang that I've seen before include "go to Scotland" , "Group (crazy or criminal?)" , "Band of delinquents" , "Go to the Scots" , "Group acting with common purpose" .)