n.1.  Dead wood, including fallen or standing trees, branches, and stumps.
2.  One or more people or things considered as burdensome,  superfluous, or serving no useful purpose: Management fired all the deadwood in the department as a cost-saving measure.
3.  also  dead wood Sports   Fallen bowling pins that remain on the alley.
4.  Nautical   A timber or set of timbers helping to connect the keel of a vessel to the stem or the sternpost.