Source : Webster's Revised Unabridged Dictionary (1913)

Apophasis \A*poph"a*sis\, n. [Gr. ? denial, fr. ? to speak out,
   to deny.] (Rhet.)
   A figure by which a speaker formally declines to take notice
   of a favorable point, but in such a manner as to produce the
   effect desired. [For example, see Mark Antony's oration.
   --Shak., Julius C[ae]sar, iii. 2.]

Source : WordNet®

apophasis
     n : mentioning something by saying it will not be mentioned