Source : Webster's Revised Unabridged Dictionary (1913)

Indifferentism \In*dif"fer*ent*ism\, n. [Cf. F.
   indiff['e]rentisme.]
   1. State of indifference; want of interest or earnestness;
      especially, a systematic apathy regarding what is true or
      false in religion or philosophy; agnosticism.

            The indifferentism which equalizes all religions and
            gives equal rights to truth and error. --Cardinal
                                                  Manning.

   2. (Metaph.) Same as {Identism}.

   3. (R. C. Ch.) A heresy consisting in an unconcern for any
      particular creed, provided the morals be right and good.
      --Gregory XVI.