The Collaborative International Dictionary of English v.0.48:

Enslave \En*slave"\, v. t. [imp. & p. p. Enslaved; p. pr. &
   vb. n. Enslaving.]
   To reduce to slavery; to make a slave of; to subject to a
   dominant influence.
   [1913 Webster]

         The conquer'd, also, and enslaved by war,
         Shall, with their freedom lost, all virtue lose.
                                                  --Milton.
   [1913 Webster]

         Pleasure admitted in undue degree
         Enslaves the will.                       --Cowper.
   [1913 Webster]

WordNet (r) 3.0 (2006):

enslave
    v 1: make a slave of; bring into servitude

Moby Thesaurus II by Grady Ward, 1.0:

94 Moby Thesaurus words for "enslave":
   adopt, appropriate, arrogate, assume, beat down, bind, break,
   browbeat, bulldoze, bully, castrate, clamp down on, coerce,
   colonize, compel, conquer, cow, daunt, deprive of freedom,
   despotize, disenfranchise, disfranchise, dominate, domineer,
   domineer over, enchain, enthrall, fetter, grind, grind down,
   henpeck, hog, hold captive, hold down, hold in bondage,
   hold in captivity, hold in leash, hold in subjection, indent,
   indenture, intimidate, jump a claim, keep down, keep under,
   lead captive, lord it over, make dependent, make free with,
   make use of, monopolize, occupy, oppress, overawe, overbear,
   overmaster, override, overrun, peonize, preempt, preoccupy,
   prepossess, press heavy on, repress, requisition, ride over,
   ride roughshod over, shackle, sit on, squat on, subject, subjugate,
   subordinate, suppress, take all of, take captive, take it all,
   take over, take possession of, take up, terrorize, trammel,
   trample down, trample upon, tread down, tread upon, tyrannize,
   tyrannize over, unman, usurp, vassalize, walk all over, walk over,
   weigh heavy on, yoke