Romantic politician supporting a master (7)
I believe the answer is:
amatory
'romantic' is the definition.
('amatory' can be a synonym of 'romantic')
'politician supporting a master' is the wordplay.
'politician' becomes 'tory' (I've seen this before**).
'supporting' is a charade indicator (letters next to each other) (in a down clue, some letters go below others).
'master' becomes 'ma'.
'a'+'ma'='ama'
'tory' put after 'ama' is 'AMATORY'.
(Other definitions for amatory that I've seen before include "Passionate" , "relating to sexual desire?" , "declaration of love" , "Loving" .)