The Collaborative International Dictionary of English v.0.48:

Employer \Em*ploy"er\, n.
   One who employs another; as, an employer of workmen.
   [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

44 Moby Thesaurus words for "employer":
   boss, business, bwana, chef, chief, church dignitary, company,
   consumer, corporation, director, ecclesiarch, elder, enjoyer,
   establishment, firm, gaffer, goodman, governor, guru, head,
   husband, liege, liege lord, lord, lord paramount, manager, master,
   organization, outfit, overlord, owner, padrone, paramount,
   paterfamilias, patriarch, patron, proprietor, rabbi, sahib,
   seigneur, seignior, starets, teacher, user