The Collaborative International Dictionary of English v.0.48:

Courb \Courb\ (k??rb), v. i. [F. courber. See Curs.]
   To bend; to stop; to bow. [Obs.]
   [1913 Webster]

         Then I courbed on my knees.              --Piers
                                                  Plowman.
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The Collaborative International Dictionary of English v.0.48:

Courb \Courb\ (k??rb), a. [F. courbe, fr. L. curvus. See
   Curve, a.]
   Curved; rounded. [Obs.]
   [1913 Webster]

         Her neck is short, her shoulders courb.  --Gower.
   [1913 Webster]