Source : Webster's Revised Unabridged Dictionary (1913)

Plausible \Plau"si*ble\, a. [L. plausibilis praiseworthy, from
   plaudere, plausum, to applaud, clap the hands, strike, beat.]
   1. Worthy of being applauded; praiseworthy; commendable;
      ready. [Obs.] --Bp. Hacket.

   2. Obtaining approbation; specifically pleasing; apparently
      right; specious; as, a plausible pretext; plausible
      manners; a plausible delusion. ``Plausible and popular
      arguments.'' --Clarendon.

   3. Using specious arguments or discourse; as, a plausible
      speaker.

Source : WordNet®

plausible
     adj 1: apparently reasonable and valid [ant: {implausible}]
     2: likely but not certain to be or become true or real; "a
        likely result"; "he foresaw a probable loss" [syn: {probable},
         {likely}] [ant: {improbable}]
     3: within the realm of credibility; "not a very likely excuse";
        "a plausible story" [syn: {likely}]
     4: appearing to merit belief or acceptance; "a credible
        witness"; "a plausible story" [syn: {credible}]