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]

WordNet (r) 3.0 (2006):

drenched
    adj 1: abundantly covered or supplied with; often used in
           combination; "drenched in moonlight"; "moon-drenched
           meadows" [syn: drenched, drenched in]

Moby Thesaurus II by Grady Ward, 1.0:

114 Moby Thesaurus words for "drenched":
   addled, awash, bathed, beery, bemused, besotted, blind drunk,
   bloated, bursting, choked, congested, crammed, crapulent,
   crapulous, crowded, deluged, dipped, distended, dizzy, dribbling,
   dripping, dripping wet, drowned, drunk, drunken, engulfed,
   far-gone, filled to overflowing, flooded, flustered, fou, full,
   gay, giddy, glorious, glutted, gorged, happy, hyperemic, immersed,
   in liquor, in spate, inebriate, inebriated, inebrious, intoxicated,
   inundated, jam-packed, jammed, jolly, macerated, maudlin, mellow,
   merry, muddled, nappy, oozing, overblown, overburdened,
   overcharged, overfed, overflowed, overflowing, overfraught,
   overfreighted, overfull, overladen, overloaded, overstocked,
   overstuffed, oversupplied, overweighted, packed, permeated,
   plethoric, ready to burst, reeling, running over, satiated,
   saturated, seeping, shikker, soaked, soaking, soaking wet, soaky,
   sodden, soggy, sopping, sopping wet, soppy, sotted, soused,
   steeped, stuffed, stuffed up, submerged, submersed, supercharged,
   supersaturated, surcharged, surfeited, swamped, swollen, tiddly,
   tipsy, under the influence, waterlogged, watersoaked, weeping,
   weltering, wet, whelmed, wringing wet