The Collaborative International Dictionary of English v.0.48:

Advantage \Ad*van"tage\ (?; 61, 48), n. [OE. avantage,
   avauntage, F. avantage, fr. avant before. See Advance, and
   cf. Vantage.]
   1. Any condition, circumstance, opportunity, or means,
      particularly favorable to success, or to any desired end;
      benefit; as, the enemy had the advantage of a more
      elevated position.
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            Give me advantage of some brief discourse. --Shak.
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            The advantages of a close alliance.   --Macaulay.
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   2. Superiority; mastery; -- with of or over.
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            Lest Satan should get an advantage of us. --2 Cor.
                                                  ii. 11.
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   3. Superiority of state, or that which gives it; benefit;
      gain; profit; as, the advantage of a good constitution.
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   4. Interest of money; increase; overplus (as the thirteenth
      in the baker's dozen). [Obs.]
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            And with advantage means to pay thy love. --Shak.
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   5. (Tennis) The first point scored after deuce.
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   Advantage ground, vantage ground. [R.] --Clarendon.

   To have the advantage of (any one), to have a personal
      knowledge of one who does not have a reciprocal knowledge.
      "You have the advantage of me; I don't remember ever to
      have had the honor." --Sheridan.

   To take advantage of, to profit by; (often used in a bad
      sense) to overreach, to outwit.
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   Syn: Advantage, Advantageous, Benefit, Beneficial.

   Usage: We speak of a thing as a benefit, or as beneficial,
          when it is simply productive of good; as, the benefits
          of early discipline; the beneficial effects of
          adversity. We speak of a thing as an advantage, or as
          advantageous, when it affords us the means of getting
          forward, and places us on a "vantage ground" for
          further effort. Hence, there is a difference between
          the benefits and the advantages of early education;
          between a beneficial and an advantageous investment of
          money.
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