High priest in power working to get over disagreement (7)
I believe the answer is:
pontiff
'high priest' is the definition.
(thesaurus)
'power working to get over disagreement' is the wordplay.
'power' becomes 'p'.
'working' becomes 'on'.
'to get over' is a charade indicator (letters next to each other).
'disagreement' becomes 'tiff' (tiff is a kind of disagreement**).
'p'+'on'+'tiff'='PONTIFF'
'in' acts as a link.
(Other definitions for pontiff that I've seen before include "Religious leader" , "Bishop" , "Title for a pope" , "High-priest" , "Head of the Roman Catholic church" .)