The Collaborative International Dictionary of English v.0.48:

Liberate \Lib"er*ate\ (-[=a]t), v. t. [imp. & p. p. Liberated
   (-[=a]`t[e^]d); p. pr. & vb. n. Liberating
   (-[=a]`t[i^]ng).] [L. liberatus, p. p. of liberare to free,
   fr. liber free. See Liberal, a., and cf. Deliver.]
   To release from restraint or bondage; to set at liberty; to
   free; to manumit; to disengage; as, to liberate a slave or
   prisoner; to liberate the mind from prejudice; to liberate
   gases.
   [1913 Webster]

   Syn: To deliver; free; release. See Deliver.
        [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

73 Moby Thesaurus words for "liberate":
   affranchise, appropriate, cast off, clear, deliver, detach,
   disburden, discharge, disembarrass, disembroil, disencumber,
   disengage, disentangle, disenthrall, disinvolve, doff, ease,
   emancipate, enfranchise, extract, extricate, free, free up, let go,
   let loose, let off, let out, loose, loosen, manumit, pilfer,
   purloin, ransom, recover, redeem, release, remove, rescue,
   retrieve, salvage, save, set at large, set at liberty, set free,
   steal, take, take off, unbar, unbind, unbolt, unbuckle, unbutton,
   unchain, unclasp, unclutter, undo, unfasten, unfetter, unglue,
   unlace, unlatch, unleash, unlock, unloose, unloosen, unscramble,
   unshackle, unsnarl, unstick, unstrap, untangle, untie,
   weigh anchor