The Collaborative International Dictionary of English v.0.48:

Drench \Drench\, n. [AS. dreng warrior, soldier, akin to Icel.
   drengr.] (O. Eng. Law)
   A military vassal mentioned in Domesday Book. [Obs.]
   --Burrill.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Drench \Drench\, v. t. [imp. & p. p. Drenched; p. pr. & vb. n.
   Drenching.] [AS. drencan to give to drink, to drench, the
   causal of drincan to drink; akin to D. drenken, Sw.
   dr[aum]nka, G. tr[aum]nken. See Drink.]
   1. To cause to drink; especially, to dose by force; to put a
      potion down the throat of, as of a horse; hence. to purge
      violently by physic.
      [1913 Webster]

            As "to fell," is "to make to fall," and "to lay," to
            make to lie." so "to drench," is "to make to drink."
                                                  --Trench.
      [1913 Webster]

   2. To steep in moisture; to wet thoroughly; to soak; to
      saturate with water or other liquid; to immerse.
      [1913 Webster]

            Now dam the ditches and the floods restrain;
            Their moisture has already drenched the plain.
                                                  --Dryden.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Drench \Drench\, n. [AS. drenc. See Drench, v. t.]
   A drink; a draught; specifically, a potion of medicine poured
   or forced down the throat; also, a potion that causes
   purging. "A drench of wine." --Dryden.
   [1913 Webster]

         Give my roan horse a drench.             --Shak.
   [1913 Webster]

WordNet (r) 3.0 (2006):

drench
    v 1: drench or submerge or be drenched or submerged; "The
         tsunami swamped every boat in the harbor" [syn: swamp,
         drench]
    2: force to drink
    3: permeate or impregnate; "The war drenched the country in
       blood" [syn: imbrue, drench]
    4: cover with liquid; pour liquid onto; "souse water on his hot
       face" [syn: drench, douse, dowse, soak, sop,
       souse]

Moby Thesaurus II by Grady Ward, 1.0:

146 Moby Thesaurus words for "drench":
   bathe, bed, bed down, beverage, break, brew, brewing, bridle,
   brush, bumper, choke, congest, cram, crowd, curry, currycomb,
   deluge, dip, douche, douse, draft, drag, drain, dram, drenching,
   drink, drop, drouk, drown, duck, ducking, dunk, dunking, feed,
   flood, flush, fodder, gargle, gentle, glut, gluttonize, gorge,
   groom, gulp, guzzle, handle, harness, hitch, imbrue, imbruement,
   imbue, imbuement, immerse, impregnate, impregnation, infiltrate,
   infiltration, infuse, infusion, inject, injection, inundate, jam,
   jam-pack, jigger, jolt, lap, lash, lave, leach, leaching, libation,
   litter, lixiviate, lixiviation, macerate, maceration, manage, milk,
   nip, overburden, overcharge, overfeed, overfill, overlade,
   overload, overstuff, overweight, pack, peg, percolate, percolation,
   permeate, permeation, portion, potation, potion, pull, pulping,
   quaff, rinse, round, round of drinks, rub down, saddle, satiate,
   saturate, saturation, seethe, seething, shot, sip, slurp, snifter,
   snort, soak, soakage, soaking, sodden, sop, sopping, souse,
   sousing, spot, steep, steeping, stuff, submerge, suck, sup,
   supercharge, supersaturate, surcharge, surfeit, swig, swill, tame,
   teem, tend, tot, train, wash, water, waterlog, wet, yoke