Offensive revolutionary deeply hurt a right-winger (10)
I believe the answer is:
derogatory
'offensive' is the definition.
(I've seen this before)
'revolutionary deeply hurt a right-winger' is the wordplay.
'revolutionary' says the letters should be written backwards.
'deeply hurt' becomes 'gored' (I can't justify this - if you can you should believe this answer much more).
'right-winger' becomes 'tory' (Tory is an example).
'gored' backwards is 'derog'.
'derog'+'a'+'tory'='DEROGATORY'
Can you help me to learn more?
(Other definitions for derogatory that I've seen before include "Showing a disrespectful attitude" , "Disparaging" , "deliberately offensive" , "Insulting" .)