The Collaborative International Dictionary of English v.0.48:
Destructiveness \De*struc"tive*ness\, n. 1. The quality of destroying or ruining. --Prynne. [1913 Webster] 2. (Phren.) The faculty supposed to impel to the commission of acts of destruction; propensity to destroy. [1913 Webster]WordNet (r) 3.0 (2006):
destructiveness n 1: the quality of causing destruction [ant: constructiveness]