The Collaborative International Dictionary of English v.0.48:

Darraign \Dar"raign\, Darrain \Dar"rain\,, v. t. [OF. deraisnier
   to explain, defend, to maintain in legal action by proof and
   reasonings, LL. derationare; de- + rationare to discourse,
   contend in law, fr. L. ratio reason, in LL., legal cause. Cf.
   Arraign, and see Reason.]
   1. To make ready to fight; to array. [Obs.]
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            Darrain your battle, for they are at hand. --Shak.
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   2. To fight out; to contest; to decide by combat. [Obs.] "To
      darrain the battle." --Chaucer .
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