WordNet (r) 3.0 (2006):

smoke screen
    n 1: (military) screen consisting of a cloud of smoke that
         obscures movements [syn: smoke screen, smokescreen]
    2: an action intended to conceal or confuse or obscure;
       "requesting new powers of surveillance is just a smokescreen
       to hide their failures" [syn: smoke screen, smokescreen]

Moby Thesaurus II by Grady Ward, 1.0:

52 Moby Thesaurus words for "smoke screen":
   alibi, apology, blind, camouflage, cloak, color, cover,
   cover story, cover-up, device, disguise, domino, excuse, facade,
   false colors, false face, false front, feint, front, gloss, guise,
   handle, incognito, lame excuse, locus standi, mask, masque,
   masquerade, mummery, ostensible motive, poor excuse, pretense,
   pretension, pretext, protective coloration, protestation,
   public motive, put-off, refuge, screen, semblance, sham, show,
   stalking-horse, stratagem, subterfuge, trick, varnish, veil, visor,
   vizard, vizard mask