The Collaborative International Dictionary of English v.0.48:

Gentilize \Gen"til*ize\, v. i. [See Gentile.]
   [1913 Webster]
   1. To live like a gentile or heathen. [Obs.] --Milton.
      [1913 Webster]

   2. To act the gentleman; -- with it (see It, 5). [Obs.]
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The Collaborative International Dictionary of English v.0.48:

Gentilize \Gen"til*ize\, v. i.
   To render gentile or gentlemanly; as, to gentilize your
   unworthy sones. [R.] --Sylvester.
   [1913 Webster]