The Collaborative International Dictionary of English v.0.48:

Judaize \Ju"da*ize\, v. i. [imp. & p. p. Judaized; p. pr. &
   vb. n. Judaizing.] [Cf. F. juda["i]ser.]
   To conform to the doctrines, observances, or methods of the
   Jews; to inculcate or impose Judaism.
   [1913 Webster]

         They . . . prevailed on the Galatians to Judaize so far
         as to observe the rites of Moses in various instances.
         They were Judaizing doctors, who taught the observation
         of the Mosaic law.                       --Bp. Bull.
   [1913 Webster]