The Collaborative International Dictionary of English v.0.48:

Deadwood \Dead"wood`\, n.
   1. (Naut.) A mass of timbers built into the bow and stern of
      a vessel to give solidity.
      [1913 Webster]

   2. Dead trees or branches; useless material.
      [1913 Webster]

   3. [fig.] People who are unproductive; -- used especially in
      reference to employees.
      [PJC]

WordNet (r) 3.0 (2006):

deadwood
    n 1: a branch or a part of a tree that is dead
    2: someone or something that is unwanted and unneeded [syn:
       fifth wheel, deadwood]

Moby Thesaurus II by Grady Ward, 1.0:

79 Moby Thesaurus words for "deadwood":
   allowance, bine, bones, bough, branch, branchedness, branchiness,
   bulge, burgeon, chaff, culm, dishwater, draff, dregs, dust, edge,
   filings, flagellum, fork, frond, garbage, gash, handicap,
   head start, hogwash, husks, leavings, lees, limb, odds, offal,
   offscourings, offshoot, orts, overhand, parings, potsherds, rags,
   ramage, ramification, raspings, refuse, runner, sarment, scion,
   scourings, scrap iron, scraps, scum, shards, shavings, shoot,
   slack, slag, slip, slop, slops, spear, spray, sprig, sprit, sprout,
   start, stolon, stubble, sucker, sweepings, swill, switch, tares,
   tendril, thallus, twig, vantage, wastage, waste, waste matter,
   wastepaper, weeds



U.S. Gazetteer Places (2000):

Deadwood, SD -- U.S. city in South Dakota
   Population (2000):    1380
   Housing Units (2000): 817
   Land area (2000):     3.776974 sq. miles (9.782318 sq. km)
   Water area (2000):    0.000000 sq. miles (0.000000 sq. km)
   Total area (2000):    3.776974 sq. miles (9.782318 sq. km)
   FIPS code:            15700
   Located within:       South Dakota (SD), FIPS 46
   Location:             44.376718 N, 103.729230 W
   ZIP Codes (1990):     57732
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Deadwood, SD
    Deadwood