WordNet (r) 3.0 (2006):

city manager
    n 1: the head of a city government [syn: mayor, city
         manager]

Moby Thesaurus II by Grady Ward, 1.0:

36 Moby Thesaurus words for "city manager":
   alderman, archon, bailie, burghermaster, burgomaster,
   cabinet member, cabinet minister, chancellor, city councilman,
   city father, commissar, commissioner, councillor, councilman,
   councilwoman, county commissioner, county supervisor, elder,
   headman, induna, legislator, lord mayor, magistrate, maire, mayor,
   minister, minister of state, portreeve, reeve, secretary,
   secretary of state, selectman, supervisor, syndic, undersecretary,
   warden