The Collaborative International Dictionary of English v.0.48:

Humanize \Hu"man*ize\, v. t. [imp. & p. p. Humanized; p. pr. &
   vb. n. Humanizing.] [Cf. F. humaniser.]
   1. To render human or humane; to soften; to make gentle by
      overcoming cruel dispositions and rude habits; to refine
      or civilize. [Also spelled humanise.]
      [1913 Webster]

            Was it the business of magic to humanize our natures
            with compassion?                      --Addison.
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   2. To give a human character or expression to. "Humanized
      divinities." --Caird.
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   3. (Med.) To convert into something human or belonging to
      man; as, to humanize vaccine lymph.
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The Collaborative International Dictionary of English v.0.48:

Humanize \Hu"man*ize\, v. i.
   To become or be made more humane; to become civilized; to be
   ameliorated.
   [1913 Webster]

         By the original law of nations, war and extirpation
         were the punishment of injury. Humanizing by degrees,
         it admitted slavery instead of death; a further step
         was the exchange of prisoners instead of slavery.
                                                  --Franklin.
   [1913 Webster]

WordNet (r) 3.0 (2006):

humanize
    v 1: make more humane; "The mayor tried to humanize life in the
         big city" [syn: humanize, humanise] [ant: dehumanise,
         dehumanize]