The Collaborative International Dictionary of English v.0.48:

Defile \De*file"\ (d[-e]*f[imac]l"), v. i. [imp. & p. p.
   Defiled (d[-e]*f[imac]ld"); 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.
   [1913 Webster]