The Collaborative International Dictionary of English v.0.48:

Advantage \Ad*van"tage\, v. t. [imp. & p. p. Advantaged; p.
   pr. & vb. n. Advantaging.] [F. avantager, fr. avantage. See
   Advance.]
   To give an advantage to; to further; to promote; to benefit;
   to profit.
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         The truth is, the archbishop's own stiffness and
         averseness to comply with the court designs, advantaged
         his adversaries against him.             --Fuller.
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         What is a man advantaged, if he gain the whole world,
         and lose himself, or be cast away?       --Luke ix. 25.
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   To advantage one's self of, to avail one's self of. [Obs.]
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