Source : Webster's Revised Unabridged Dictionary (1913)

Poltroon \Pol*troon"\, a.
   Base; vile; contemptible; cowardly.

Poltroon \Pol*troon"\, n. [F. poltron, from It. poltrone an idle
   fellow, sluggard, coward, poltro idle, lazy, also, bed, fr.
   OHG. polstar, bolstar, cushion, G. polster, akin to E.
   bolster. See {Bolster}.]
   An arrant coward; a dastard; a craven; a mean-spirited
   wretch. --Shak.

Source : WordNet®

poltroon
     adj : characterized by complete cowardliness

poltroon
     n : an abject coward [syn: {craven}, {recreant}]