The Collaborative International Dictionary of English v.0.48:

Contraption \Con*trap"tion\, n.
   A contrivance; a new-fangled device; -- used scornfully.
   [Colloq. or Dial.] -- Con*trap"tious, a.

         We all remember some of the extraordinary contraptions
         which have been thus evolved and put upon the market.
                                                  --F. M. Ware.
   [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

contraption
    n 1: a device or control that is very useful for a particular
         job [syn: appliance, contraption, contrivance,
         convenience, gadget, gizmo, gismo, widget]

Moby Thesaurus II by Grady Ward, 1.0:

22 Moby Thesaurus words for "contraption":
   apparatus, contrivance, device, gadget, gimcrack, gimmick, gizmo,
   hand tool, implement, instrument, means, mechanical device,
   mechanism, power tool, precision tool, speed tool, thingumabob,
   thingumajig, thingummy, tool, utensil, widget