The Collaborative International Dictionary of English v.0.48:

Trump \Trump\, n. [A corruption of triumph, F. triomphe. See
   Triumph, and cf. Trump a trumpet.]
   1. A winning card; one of a particular suit (usually
      determined by chance for each deal) any card of which
      takes any card of the other suits.
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   2. An old game with cards, nearly the same as whist; --
      called also ruff. --Decker.
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   3. A good fellow; an excellent person. [Slang]
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            Alfred is a trump, I think you say.   --Thackeray.
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   To put to one's trumps, or To put on one's trumps, to
      force to the last expedient, or to the utmost exertion.
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            But when kings come so low as to fawn upon
            philosophy, which before they neither valued nor
            understood, it is a sign that fails not, they are
            then put to their last trump.         --Milton.
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            Put the housekeeper to her trumps to accommodate
            them.                                 --W. Irving.
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