Office-holder lying (9)
I believe the answer is:
incumbent
This clue might be a double definition.
'office-holder' is the first definition.
(I've seen this before)
'lying' is the second definition.
Both the definition and answer are adjectives. Maybe there's an association between them I don't understand?
Can you help me to learn more?
(Other definitions for incumbent that I've seen before include "Holder of an office or post" , "Necessary - office-holder" , "Functionary" , "official?" , "vicar?" .)