Source : Webster's Revised Unabridged Dictionary (1913)

Moon \Moon\, v. t. [imp. & p. p. {Mooned}; p. pr. & vb. n.
   {Mooning}.]
   To expose to the rays of the moon.

         If they have it to be exceeding white indeed, they
         seethe it yet once more, after it hath been thus sunned
         and mooned.                              --Holland.