Source : Webster's Revised Unabridged Dictionary (1913)

Scupper \Scup"per\, n. [OF. escopir, escupir, to spit, perhaps
   for escospir, L. ex + conspuere to spit upon; pref. con- +
   spuere to spit. Cf. {Spit}, v.] (Naut.)
   An opening cut through the waterway and bulwarks of a ship,
   so that water falling on deck may flow overboard; -- called
   also {scupper hole}.

Source : WordNet®

scupper
     n : drain that allows water on the deck of a vessel to flow
         overboard

scupper
     v 1: wait in hiding to attack [syn: {ambush}, {bushwhack}, {waylay},
           {lurk}, {ambuscade}, {lie in wait}]
     2: put in a dangerous, disadvantageous, or difficult position
        [syn: {queer}, {expose}, {endanger}, {peril}]