Source : Webster's Revised Unabridged Dictionary (1913)

Inconclusive \In`con*clu"sive\, a.
   Not conclusive; leading to no conclusion; not closing or
   settling a point in debate, or a doubtful question; as,
   evidence is inconclusive when it does not exhibit the truth
   of a disputed case in such a manner as to satisfy the mind,
   and put an end to debate or doubt.

         Arguments . . . inconclusive and impertinent. --South.
   -- {In`con*clu"sive*ly}, adv. -- {In`con*clu"sive*ness}, n.

Source : WordNet®

inconclusiveness
     n : the quality of being inconclusive [ant: {finality}]