The Collaborative International Dictionary of English v.0.48:

Sop \Sop\, v. t. [imp. & p. p. Sopped; p. pr. & vb. n.
   Sopping.]
   To steep or dip in any liquid.
   [1913 Webster]

WordNet (r) 3.0 (2006):

sopping
    adv 1: extremely wet; "dripping wet"; "soaking wet" [syn:
           soaking, sopping, dripping]

Moby Thesaurus II by Grady Ward, 1.0:

70 Moby Thesaurus words for "sopping":
   awash, bathed, brewing, dampening, deluged, dipped, drench,
   drenched, drenching, dribbling, dripping, dripping wet, drowned,
   ducking, dunking, engulfed, flooded, humectant, imbruement,
   imbuement, immersed, impregnation, infiltration, infusion,
   injection, inundated, irrigational, irriguous, leaching,
   lixiviation, macerated, maceration, moistening, oozing, overflowed,
   percolation, permeated, permeation, pulping, saturated, saturation,
   seeping, seething, soak, soakage, soaked, soaking, soaking wet,
   soaky, sodden, soggy, sopping wet, soppy, souse, soused, sousing,
   steeped, steeping, submerged, submersed, swamped, watering,
   waterlogged, watersoaked, weeping, weltering, wet, wetting,
   whelmed, wringing wet