DEFILEMENT is a 10 letter word that starts with D.

1. \De*file"ment\, n. [Cf. F. d['e]filement. See
   {Defile}] (Mil.)
   The protection of the interior walls of a fortification from
   an enfilading fire, as by covering them, or by a high parapet
   on the exposed side.
   
   

2. \De*file"ment\, n. [From 3d {Defile}.]
   The act of defiling, or state of being defiled, whether
   physically or morally; pollution; foulness; dirtiness;
   uncleanness.
   
         Defilements of the flesh.                --Hopkins.
   
         The chaste can not rake into such filth without danger
         of defilement.                           --Addison.