The Collaborative International Dictionary of English v.0.48:
Conclusiveness \Con*clu"sive*ness\, n. The quality of being conclusive; decisiveness. [1913 Webster]WordNet (r) 3.0 (2006):
conclusiveness n 1: the quality of being final or definitely settled; "the finality of death" [syn: finality, conclusiveness, decisiveness] [ant: inconclusiveness]