WordNet (r) 3.0 (2006):

ruling class
    n 1: the class of people exerting power or authority [syn:
         ruling class, people in power]

Moby Thesaurus II by Grady Ward, 1.0:

120 Moby Thesaurus words for "ruling class":
   aedileship, archbishopric, archiepiscopacy, archiepiscopate,
   aristocracy, barons, bishopric, bureaucracy, chairmanship,
   chancellery, chancellorate, chancellorship, chiefery, chiefry,
   chieftaincy, chieftainry, chieftainship, consulate, consulship,
   cream, deanery, dictatorship, dictature, directorate, directorship,
   elite, emirate, episcopacy, establishment, governorship, headship,
   hegemony, hierarchy, higher echelons, higher-ups, leadership,
   lords of creation, lordship, magistracy, magistrateship,
   magistrature, management, masterdom, mastership, mastery,
   mayoralty, mayorship, metropolitanate, metropolitanship, ministry,
   nobility, officialdom, overlapping, papacy, pashadom, pashalic,
   patriarchate, patriarchy, pontificality, pontificate, popedom,
   popehood, popeship, power elite, power structure, prefectship,
   prefecture, prelacy, premiership, presidency, presidentship,
   prime-ministership, prime-ministry, princedom, princeship,
   principality, proconsulate, proconsulship, protectorate,
   protectorship, provostry, provostship, rectorate, rectorship,
   regency, regentship, ruling circles, ruling classes, seigniory,
   seneschalship, seneschalsy, sheikhdom, sheriffalty, sheriffcy,
   sheriffdom, shrievalty, supervisorship, suzerainship, suzerainty,
   the Establishment, the administration, the authorities, the best,
   the best people, the brass, the ingroup, the interests,
   the people upstairs, the power elite, the power structure, the top,
   them, they, top brass, top people, tribunate, upper class,
   upper crust, vizierate, viziership