overlord

from WordNet (r) 3.0 (2006)

overlord
    n 1: a person who has general authority over others [syn:
         {overlord}, {master}, {lord}]

from The Collaborative International Dictionary of English v.0.48

Overlord \O"ver*lord`\, n.
   One who is lord over another or others; a superior lord; a
   master. --Freeman.
   [1913 Webster]

from Moby Thesaurus II by Grady Ward, 1.0

51 Moby Thesaurus words for "overlord":
      anointed king, boss, bwana, chef, chief, chieftain,
      church dignitary, crowned head, dynast, ecclesiarch, elder,
      emperor, employer, goodman, grand duke, guru, high chief, husband,
      imperator, king, king-emperor, kinglet, liege, liege lord, lord,
      lord paramount, majesty, master, monarch, padrone, paramount,
      paterfamilias, patriarch, patron, petty king, potentate, prince,
      prince consort, rabbi, royal, royal personage, royalty, ruler,
      sahib, seigneur, seignior, sovereign, starets, suzerain, teacher,
      tetrarch