The Collaborative International Dictionary of English v.0.48:

Lubricate \Lu"bri*cate\, v. t. [L. lubricatus, p. p. of
   lubricare to lubricate. See Lubric.]
   1. To make smooth or slippery; as, mucilaginous and
      saponaceous remedies lubricate the parts to which they are
      applied. --S. Sharp.
      [1913 Webster]

            Supples, lubricates, and keeps in play,
            The various movements of this nice machine. --Young.
      [1913 Webster]

   2. To apply a lubricant to, as oil or tallow.
      [1913 Webster]

   3. Hence: To reduce social frictions or difficulties between
      people, thus making cooperation easier and joint action
      smoother.
      [PJC]

   4. To inebriate by supplying with alcoholic beverages.
      [slang]
      [PJC]

WordNet (r) 3.0 (2006):

lubricate
    v 1: have lubricating properties; "the liquid in this can
         lubricates well"
    2: apply a lubricant to; "lubricate my car" [syn: lubricate,
       lube]
    3: make slippery or smooth through the application of a
       lubricant; "lubricate the key"

Moby Thesaurus II by Grady Ward, 1.0:

69 Moby Thesaurus words for "lubricate":
   aid, anoint, beeswax, buy, buy off, clear the way, dab, daub, drag,
   dress, dub, ease, embrocate, equalize, even, expedite, explain,
   facilitate, fix, flatten, glycerolate, grade, grease,
   grease the ways, grease the wheels, harrow, hasten, have,
   help along, lard, lay, level, loose, make clear, make way for, mow,
   oil, open the way, open up, pave the way, plane, planish, plaster,
   pomade, prepare the way, quicken, remove friction,
   run interference for, salve, shave, simplify, slick, slick on,
   smear, smooth, smooth down, smooth out, smooth the way,
   soap the ways, sop, speed, square, tamper with, unbar, unblock,
   unclog, unguent, unjam, wax