Source : Webster's Revised Unabridged Dictionary (1913)

Defile \De*file"\, v. i. [imp. & p. p. {Defiled}; p. pr. & vb.
   n. {Defiling}.] [F. d['e]filer; pref. d['e]-, for des- (L.
   dis-) + file a row or line. See {File} a row.]
   To march off in a line, file by file; to file off.

Defile \De*file"\, v. t. (Mil.)
   Same as {Defilade}.

Defile \De*file"\ (?; 277), n. [Cf. F. d['e]fil['e], fr.
   d['e]filer to defile.]
   1. Any narrow passage or gorge in which troops can march only
      in a file, or with a narrow front; a long, narrow pass
      between hills, rocks, etc.

   2. (Mil.) The act of defilading a fortress, or of raising the
      exterior works in order to protect the interior. See
      {Defilade}.

Defile \De*file"\, v. t. [OE. defoulen, -foilen, to tread down,
   OF. defouler; de- + fouler to trample (see {Full}, v. t.),
   and OE. defoulen to foul (influenced in form by the older
   verb defoilen). See {File} to defile, {Foul}, {Defoul}.]
   1. To make foul or impure; to make filthy; to dirty; to
      befoul; to pollute.

            They that touch pitch will be defiled. --Shak.

   2. To soil or sully; to tarnish, as reputation; to taint.

            He is . . . among the greatest prelates of this age,
            however his character may be defiled by . . . dirty
            hands.                                --Swift.

   3. To injure in purity of character; to corrupt.

            Defile not yourselves with the idols of Egypt.
                                                  --Ezek. xx. 7.

   4. To corrupt the chastity of; to debauch; to violate.

            The husband murder'd and the wife defiled. --Prior.

   5. To make ceremonially unclean; to pollute.

            That which dieth of itself, or is torn with beasts,
            he shall not eat to defile therewith. --Lev. xxii.
                                                  8.

Source : WordNet®

defile
     n : a narrow pass (especially one between mountains) [syn: {gorge}]

defile
     v 1: place under suspicion or cast doubt upon; "sully someone's
          reputation" [syn: {sully}, {corrupt}, {taint}, {cloud}]
     2: make dirty or spotty, as by exposure to air; also used
        metaphorically; "The silver was tarnished by the long
        exposure to the air"; "Her reputation was sullied after
        the affair with a married man" [syn: {tarnish}, {stain}, {maculate},
         {sully}]
     3: spot, stain, or pollute; "The townspeople defiled the river
        by emptying raw sewage into it" [syn: {foul}, {befoul}, {maculate}]