Assist excellent Democrat (3)
I believe the answer is:
aid
'assist' is the definition.
(synonyms)
'excellent democrat' is the wordplay.
'excellent' becomes 'ai' (resembles 'A1', old-fashioned term for excellent).
'democrat' becomes 'd'.
'ai'+'d'='AID'
(Other definitions for aid that I've seen before include "Help or succour" , "Good point" , "Help. Assist" , "Help, assistance" , "Care and help" .)