WordNet (r) 3.0 (2006):

camouflaged
    adj 1: made invisible by means of protective coloring

Moby Thesaurus II by Grady Ward, 1.0:

33 Moby Thesaurus words for "camouflaged":
   behind the curtain, behind the scenes, concealed, disguised,
   hidden, imperceptible, in disguise, incog, incognito,
   indiscernible, insensible, invisible, latent, masked, masquerading,
   out of sight, secret, sightless, submerged, unapparent, unbeheld,
   unbeholdable, undiscernible, unnoticed, unobserved, unperceivable,
   unperceived, unrealized, unseeable, unseen, unviewed, unwitnessed,
   viewless