The Collaborative International Dictionary of English v.0.48:

Soak \Soak\, v. i.
   1. To lie steeping in water or other liquid; to become
      sturated; as, let the cloth lie and soak.
      [1913 Webster]

   2. To enter (into something) by pores or interstices; as,
      water soaks into the earth or other porous matter.
      [1913 Webster]

   3. To drink intemperately or gluttonously. [Slang]
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Soak \Soak\, v. t. [imp. & p. p. Soaked; p. pr. & vb. n.
   Soaking.] [OE. soken, AS. socian to sioak, steep, fr.
   s?can, s?gan, to suck. See Suck.]
   1. To cause or suffer to lie in a fluid till the substance
      has imbibed what it can contain; to macerate in water or
      other liquid; to steep, as for the purpose of softening or
      freshening; as, to soak cloth; to soak bread; to soak salt
      meat, salt fish, or the like.
      [1913 Webster]

   2. To drench; to wet thoroughly.
      [1913 Webster]

            Their land shall be soaked with blood. --Isa. xxiv.
                                                  7.
      [1913 Webster]

   3. To draw in by the pores, or through small passages; as, a
      sponge soaks up water; the skin soaks in moisture.
      [1913 Webster]

   4. To make (its way) by entering pores or interstices; --
      often with through.
      [1913 Webster]

            The rivulet beneath soaked its way obscurely through
            wreaths of snow.                      --Sir W.
                                                  Scott.
      [1913 Webster]

   5. Fig.: To absorb; to drain. [Obs.] --Sir H. Wotton.
      [1913 Webster]

WordNet (r) 3.0 (2006):

soak
    n 1: the process of becoming softened and saturated as a
         consequence of being immersed in water (or other liquid);
         "a good soak put life back in the wagon" [syn: soak,
         soakage, soaking]
    2: washing something by allowing it to soak [syn: soak,
       soaking]
    v 1: submerge in a liquid; "I soaked in the hot tub for an hour"
    2: rip off; ask an unreasonable price [syn: overcharge,
       soak, surcharge, gazump, fleece, plume, pluck,
       rob, hook] [ant: undercharge]
    3: cover with liquid; pour liquid onto; "souse water on his hot
       face" [syn: drench, douse, dowse, soak, sop,
       souse]
    4: leave as a guarantee in return for money; "pawn your
       grandfather's gold watch" [syn: pawn, soak, hock]
    5: beat severely
    6: make drunk (with alcoholic drinks) [syn: intoxicate,
       soak, inebriate]
    7: become drunk or drink excessively [syn: souse, soak,
       inebriate, hit it up]
    8: fill, soak, or imbue totally; "soak the bandage with
       disinfectant" [syn: soak, imbue]
    9: heat a metal prior to working it

Moby Thesaurus II by Grady Ward, 1.0:

235 Moby Thesaurus words for "soak":
   absorb, alcoholic, assimilate, bang, bash, bat, bathe, belt,
   bender, bib, bibber, biff, bleed, bleed white, bonk, booze,
   boozehound, boozer, bottle sucker, brannigan, brew, brewing, bum,
   bust, busy, choke, clap, clip, clobber, clout, clump, coldcock,
   concentrate, congest, crack, cram, crowd, cut, dash, deal,
   deal a blow, deck, decoct, deluge, dip, dipsomaniac, distill,
   douche, douse, dowse, drain the cup, dram, draw, drench, drenching,
   drink, drink bottoms-up, drink deep, drink hard, drink off,
   drink up, drinker, drouk, drown, drunk, drunkard, ducking, dunking,
   elbow bender, engross, essentialize, exploit, express, fetch,
   fetch a blow, fleece, flush, follow strong drink, gargle, ginhound,
   glut, gluttonize, gorge, gouge, grog, guzzle, guzzler, hit,
   hit a clip, hold up, hooch hound, imbibe, imbrue, imbruement,
   imbue, imbuement, immerse, impregnate, impregnation, inebriate,
   infiltrate, infiltration, infuse, infusion, inject, injection,
   inundate, jab, jag, jam, jam-pack, knock, knock back, knock cold,
   knock down, knock out, lap, lap up, lave, leach, leaching, learn,
   let have it, liquor up, lixiviate, lixiviation, lush, lusher,
   macerate, maceration, melt down, nip, occupy, overburden,
   overcharge, overfeed, overfill, overlade, overload, overprice,
   overstuff, overtax, overweight, pack, paste, penetrate, percolate,
   percolation, permeate, permeation, pervade, plunk, poke, press out,
   profiteer, pulping, punch, quaff, refine, render, rinse, rum hound,
   rummy, satiate, saturate, saturation, screw, seethe, seething, sip,
   skin, slam, slog, slug, smack, smite, snap, soak up, soakage,
   soaker, soaking, sock, sodden, sop, sopping, sot, souse, sousing,
   sponge, sponge up, steep, steeping, stew, stick, sting, strike,
   strike at, stuff, submerge, sup, supercharge, supersaturate,
   surcharge, surfeit, swat, swig, swill, swillbelly, swillbowl,
   swillpot, swindle, swipe, take in, tank up, tear, thump, thwack,
   tipple, tippler, tope, toper, toss down, toss off, victimize,
   wallop, wash, waterlog, wet, whack, wham, whop, wino, wring,
   wring out, yerk