The Collaborative International Dictionary of English v.0.48:

Helot \He"lot\ (?; 277), n. [L. Helotes, Hilotae, pl., fr. Gr.
   E'e`lws and E'elw`ths a bondman or serf of the Spartans; so
   named from 'Elos, a town of Laconia, whose inhabitants were
   enslaved; or perh. akin to e`lei^n to take, conquer, used as
   2d aor. of ?.]
   A slave in ancient Sparta; a Spartan serf; hence, a slave or
   serf.
   [1913 Webster]

         Those unfortunates, the Helots of mankind, more or less
         numerous in every community.             --I. Taylor.
   [1913 Webster]

WordNet (r) 3.0 (2006):

helot
    n 1: (Middle Ages) a person who is bound to the land and owned
         by the feudal lord [syn: serf, helot, villein]

Moby Thesaurus II by Grady Ward, 1.0:

66 Moby Thesaurus words for "helot":
   apple-polisher, ass-licker, backscratcher, backslapper, bondmaid,
   bondman, bondslave, bondsman, bondswoman, bootlick, bootlicker,
   brown-nose, brownie, captive, chattel, chattel slave, churl,
   clawback, concubine, courtier, creature, cringer, debt slave, dupe,
   fawner, flatterer, flunky, footlicker, galley slave, groveler,
   handshaker, homager, instrument, jackal, kowtower, lackey,
   led captain, lickspit, lickspittle, liege, liege man,
   liege subject, mealymouth, minion, odalisque, peon, puppet, serf,
   servant, slave, spaniel, stooge, subject, suck, sycophant, theow,
   thrall, timeserver, toad, toady, tool, truckler, tufthunter,
   vassal, villein, yes-man