Source : Webster's Revised Unabridged Dictionary (1913)

Specious \Spe"cious\, a. [L. speciosusgood-looking, beautiful,
   specious, fr. species look, show, appearance; cf. F.
   sp['e]coeux. See {Species}.]
   1. Presenting a pleasing appearance; pleasing in form or
      look; showy.

            Some [serpents] specious and beautiful to the eye.
                                                  --Bp.
                                                  Richardson.

            The rest, far greater part, Will deem in outward
            rites and specious forms Religion satisfied.
                                                  --Milton.

   2. Apparently right; superficially fair, just, or correct,
      but not so in reality; appearing well at first view;
      plausible; as, specious reasoning; a specious argument.

            Misled for a moment by the specious names of
            religion, liberty, and property.      --Macaulay.

            In consequence of their greater command of specious
            expression.                           --J. Morley.

   Syn: Plausible; showy; ostensible; colorable; feasible. See
        {Plausible}. -- {Spe"xious*ly}, adv. --
        {Spe"cious*ness}, n.

Source : WordNet®

specious
     adj 1: plausible but false; "specious reasoning"; "the spurious
            inferences from obsolescent notions of causality"-
            Ethel Albert [syn: {spurious}]
     2: plausible but false; "a specious claim"
     3: based on pretense; deceptively pleasing; "the gilded and
        perfumed but inwardly rotten nobility"; "meretricious
        praise"; "a meretricious argument" [syn: {gilded}, {meretricious}]