The Collaborative International Dictionary of English v.0.48:

Craven \Cra"ven\, v. t. [imp. & p. p. Cravened (-v'nd); p. pr.
   & vb. n. Cravening.]
   To make recreant, weak, spiritless, or cowardly. [Obs.]
   [1913 Webster]

         There is a prohibition so divine,
         That cravens my weak hand.               --Shak.
   [1913 Webster]