The Collaborative International Dictionary of English v.0.48:

dock-walloper \dock-walloper\ n.
   a laborer who loads and unloads vessels in a port.

   Syn: stevedore, loader, longshoreman, docker, dockhand, dock
        worker, lumper.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

dock-walloper
    n 1: a laborer who loads and unloads vessels in a port [syn:
         stevedore, loader, longshoreman, docker,
         dockhand, dock worker, dockworker, dock-walloper,
         lumper]