The Collaborative International Dictionary of English v.0.48:

Flay \Flay\ (fl[=a]), v. t. [imp. & p. p. Flayed (fl[=a]d); p.
   pr. & vb. n. Flaying.] [OE. flean, flan, AS. fle['a]n; akin
   to D. vlaen, Icel. fl[=a], Sw. fl[*a], Dan. flaae, cf. Lith.
   pleszti to tear, plyszti, v.i., to burst, tear; perh. akin to
   E. flag a flat stone, flaw.]
   To skin; to strip off the skin or surface of; as, to flay an
   ox; to flay the green earth.
   [1913 Webster]

         With her nails
         She 'll flay thy wolfish visage.         --Shak.
   [1913 Webster]

WordNet (r) 3.0 (2006):

flay
    v 1: strip the skin off

Moby Thesaurus II by Grady Ward, 1.0:

56 Moby Thesaurus words for "flay":
   assail, attack, bark, berate, bleed, bleed white, blister,
   castigate, decorticate, defoliate, denude, deplume, despoil,
   dismember, displume, divest, drain, draw and quarter, dry,
   excoriate, exhaust, fleece, fustigate, impoverish, lacerate, lash,
   maim, mangle, milk, mutilate, pare, peel, pick clean,
   pick to pieces, pluck, pull apart, roast, scalp, scarify, scathe,
   scorch, scourge, shear, shred, skin, skin alive, slash, strip,
   strip bare, suck dry, take apart, tear apart, tear to pieces,
   tear to tatters, tongue-lash, trounce