The Collaborative International Dictionary of English v.0.48:

Cow \Cow\, v. t. [imp. & p. p. Cowed (koud); p. pr. & vb. n.
   Cowing.] [Cf. Icel. kuga, Sw. kufva to check, subdue, Dan.
   kue. Cf. Cuff, v. t.]
   To depress with fear; to daunt the spirits or courage of; to
   overawe.
   [1913 Webster]

         To vanquish a people already cowed.      --Shak.
   [1913 Webster]

         THe French king was cowed.               --J. R. Green.
   [1913 Webster]