The Collaborative International Dictionary of English v.0.48:

Gantlet \Gant"let\, n. [Gantlet is corrupted fr. gantlope;
   gantlope is for gatelope, Sw. gatlopp, orig., a running down
   a lane; gata street, lane + lopp course, career, akin to
   l["o]pa to run. See Gate a way, and Leap.]
   A military punishment formerly in use, wherein the offender
   was made to run between two files of men facing one another,
   who struck him as he passed.
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   To run the gantlet, to suffer the punishment of the
      gantlet; hence, to go through the ordeal of severe
      criticism or controversy, or ill-treatment at many hands.
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            Winthrop ran the gantlet of daily slights.
                                                  --Palfrey.
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   Note: Written also, but less properly, gauntlet.
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