Source : Webster's Revised Unabridged Dictionary (1913)

Expurgation \Ex`pur*ga"tion\, n. [L. expurgatio justification,
   excuse: cf. F. expurgation.]
   The act of expurgating, purging, or cleansing; purification
   from anything noxious, offensive, sinful, or erroneous.
   --Milton.

Source : WordNet®

expurgation
     n : the deletion of objectionable parts from a literary work
         [syn: {castration}]