The Collaborative International Dictionary of English v.0.48:

Disguise \Dis*guise"\ (?; 232), v. t. [imp. & p. p. Disguised;
   p. pr. & vb. n. Disguising.] [OE. desguisen, disgisen,
   degisen, OF. desguisier, F. d['e]guiser; pref. des- (L. dis-)
   + guise. See Guise.]
   1. To change the guise or appearance of; especially, to
      conceal by an unusual dress, or one intended to mislead or
      deceive.
      [1913 Webster]

            Bunyan was forced to disguise himself as a wagoner.
                                                  --Macaulay.
      [1913 Webster]

   2. To hide by a counterfeit appearance; to cloak by a false
      show; to mask; as, to disguise anger; to disguise one's
      sentiments, character, or intentions.
      [1913 Webster]

            All God's angels come to us disguised. --Lowell.
      [1913 Webster]

   3. To affect or change by liquor; to intoxicate.
      [1913 Webster]

            I have just left the right worshipful, and his
            myrmidons, about a sneaker of five gallons; the
            whole magistracy was pretty well disguised before I
            gave them the ship.                   --Spectator.

   Syn: To conceal; hide; mask; dissemble; dissimulate; feign;
        pretend; secrete. See Conceal.
        [1913 Webster]

WordNet (r) 3.0 (2006):

disguised
    adj 1: having its true character concealed with the intent of
           misleading; "hidden agenda"; "masked threat" [syn:
           cloaked, disguised, masked]

Moby Thesaurus II by Grady Ward, 1.0:

77 Moby Thesaurus words for "disguised":
   appareled, arrayed, attired, bedecked, behind the curtain,
   behind the scenes, boozy, breeched, camouflaged, canned, capped,
   chausse, clad, cloaked, clothed, coifed, concealed, costumed,
   decked, dight, dressed, drunk, endued, garbed, garmented, gowned,
   habilimented, habited, hidden, hooded, imperceptible, in disguise,
   incog, incognito, indiscernible, inebriated, insensible, invested,
   invisible, latent, liveried, mantled, masked, masquerading,
   muddled, out of sight, pantalooned, pixilated, plastered,
   raimented, rigged out, robed, secret, shod, shoed, sightless,
   submerged, tired, togged, tricked out, trousered, unapparent,
   unbeheld, unbeholdable, undiscernible, unnoticed, unobserved,
   unperceivable, unperceived, unrealized, unseeable, unseen,
   unviewed, unwitnessed, vested, vestmented, viewless