Senior figure's urge to support party (5)
I believe the answer is:
doyen
'senior' is the definition.
(I've seen this before)
'urge to support party' is the wordplay.
'urge' becomes 'yen' (I've seen this before).
'to support' means one lot of letters go next to another.
'party' becomes 'do' (do is a kind of party).
'yen' after 'do' is 'DOYEN'.
'figure's' acts as a link.
I am not very happy about this link. It may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for doyen that I've seen before include "The oldest of the members" , "Grand old man" , "respected figure" , "The most respected among experts" , "As senior statesman" .)