Source : Webster's Revised Unabridged Dictionary (1913)

Self-contradiction \Self`-con`tra*dic"tion\, n.
   The act of contradicting one's self or itself; repugnancy in
   conceptions or in terms; a proposition consisting of two
   members, one of which contradicts the other; as, to be and
   not to be at the same time is a self-contradiction.