The Collaborative International Dictionary of English v.0.48:

Pusillanimous \Pu`sil*lan"i*mous\, a. [L. pusillanimis; pusillus
   very little (dim. of pusus a little boy; cf. puer a boy, E.
   puerile) + animus the mind: cf. F. pusillanime. See
   Animosity.]
   1. Destitute of a manly or courageous strength and firmness
      of mind; of weak spirit; mean-spirited; spiritless;
      cowardly; -- said of persons, as, a pusillanimous prince.
      [1913 Webster]

   2. Evincing, or characterized by, weakness of mind, and want
      of courage; feeble; as, pusillanimous counsels. "A low and
      pusillanimous spirit." --Burke.
      [1913 Webster]

   Syn: Cowardly; dastardly; mean-spirited; fainthearted; timid;
        weak; feeble.
        [1913 Webster]

WordNet (r) 3.0 (2006):

pusillanimous
    adj 1: lacking in courage and manly strength and resolution;
           contemptibly fearful [syn: pusillanimous, poor-
           spirited, unmanly]