The Collaborative International Dictionary of English v.0.48:

Charg'e d'affaires \Char`g['e]" d'af`faires"\, n.; pl.
   Charg['e]s d'affaires. [F., "charged with affairs."]
   A diplomatic representative, or minister of an inferior
   grade, accredited by the government of one state to the
   minister of foreign affairs of another; also, a substitute,
   ad interim, for an ambassador or minister plenipotentiary.
   [1913 Webster]