Desire to act as senior member (5)
I believe the answer is:
doyen
'senior member' is the definition.
(I've seen this before)
'desire to act' is the wordplay.
'desire' becomes 'yen' (yen is a kind of desire).
'to' says to put letters next to each other (I've seen this in other clues).
'act' becomes 'do' (I've seen this in other clues).
'yen' after 'do' is 'DOYEN'.
'as' is the link.
(Other definitions for doyen that I've seen before include "The most respected among experts" , "Senior practitioner" , "As senior statesman" , "Top expert in a field" , "Prominent group member" .)