The Collaborative International Dictionary of English v.0.48:

Blush \Blush\, n.
   1. A suffusion of the cheeks or face with red, as from a
      sense of shame, confusion, or modesty.
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            The rosy blush of love.               --Trumbull.
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   2. A red or reddish color; a rosy tint.
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            Light's last blushes tinged the distant hills.
                                                  --Lyttleton.
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   At first blush, or At the first blush, at the first
      appearance or view. "At the first blush, we thought they
      had been ships come from France." --Hakluyt.

   Note: This phrase is used now more of ideas, opinions, etc.,
         than of material things. "All purely identical
         propositions, obviously, and at first blush, appear,"
         etc. --Locke.

   To put to the blush, to cause to blush with shame; to put
      to shame.
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