The Collaborative International Dictionary of English v.0.48:

Scaramouch \Scar"a*mouch`\, n. [F. scaramouche, It. scaramuccio,
   scaramuccia, originally the name of a celebrated Italian
   comedian; cf. It. scaramuccia, scaramuccio, F. escarmouche,
   skirmish. Cf. Skirmish.]
   A personage in the old Italian comedy (derived from Spain)
   characterized by great boastfulness and poltroonery; hence, a
   person of like characteristics; a buffoon.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Scaramouch
    n 1: a stock character in commedia dell'arte depicted as a
         boastful coward [syn: Scaramouch, Scaramouche]