The Collaborative International Dictionary of English v.0.48:

Sciomachy \Sci*om"a*chy\, n. [Gr. ?, ?; ? a shadow + ? battle:
   cf. F. sciomachie, sciamachie.]
   A fighting with a shadow; a mock contest; an imaginary or
   futile combat. [Written also scimachy.] --Cowley.
   [1913 Webster]