Mayor taking umbrage, sort to get upset (11)
I believe the answer is:
burgomaster
'mayor' is the definition.
(burgomaster is a kind of mayor)
'umbrage sort to get upset' is the wordplay.
'to get upset' indicates anagramming the letters (I've seen 'getting upset' mean this).
'umbrage'+'sort'='umbragesort'
'umbragesort' anagrammed gives 'BURGOMASTER'.
'taking' is the link.
(Other definitions for burgomaster that I've seen before include "Dutch mayor" , "Mayor in Germany, Austria, etc" .)