The Collaborative International Dictionary of English v.0.48:

Blush \Blush\ (bl[u^]sh) v. i. [imp. & p. p. Blushed
   (bl[u^]sht); p. pr. & vb. n. Blushing.] [OE. bluschen to
   shine, look, turn red, AS. blyscan to glow; akin to blysa a
   torch, [=a]bl[=y]sian to blush, D. blozen, Dan. blusse to
   blaze, blush.]
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   1. To become suffused with red in the cheeks, as from a sense
      of shame, modesty, or confusion; to become red from such
      cause, as the cheeks or face.
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            To the nuptial bower
            I led her blushing like the morn.     --Milton.
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            In the presence of the shameless and unblushing, the
            young offender is ashamed to blush.   --Buckminster.
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            He would stroke
            The head of modest and ingenuous worth,
            That blushed at its own praise.       --Cowper.
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   2. To grow red; to have a red or rosy color.
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            The sun of heaven, methought, was loth to set,
            But stayed, and made the western welkin blush.
                                                  --Shak.
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   3. To have a warm and delicate color, as some roses and other
      flowers.
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            Full many a flower is born to blush unseen. --T.
                                                  Gray.
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