A stuck-up politician, rude (10)
I believe the answer is:
Here is my best explanation:
'rude' is the definition.
'a stuck-up politician' is the subsidiary indication.
'stuck' becomes 'gored'.
'up' says the letters should be written backwards (in down clue: letters go upwards).
'politician' becomes 'tory' (**).
'agored' backwards is 'deroga'.
(Other definitions for derogatory that I've seen before include "Showing a disrespectful attitude" and "Insulting".)