Source : Webster's Revised Unabridged Dictionary (1913)

Adiaphorous \Ad`i*aph"o*rous\, a. [Gr. ?; 'a priv. + ?
   different; ? through + ? to bear.]
   1. Indifferent or neutral. --Jer. Taylor.

   2. (Med.) Incapable of doing either harm or good, as some
      medicines. --Dunglison.