1) Harmfulness 2) Injuriousness 
[phrenology] Destructiveness is a faculty from the discipline of phrenology. ==Definition== Destructiveness is the area of dynamic energy. Some authors call it Executive Energy. It stands for force, dynamism, fighting spirit (for any cause). It accumulates energy, basically for self-preservation. If untempered by the Moral faculties, which ...
• (n.) The faculty supposed to impel to the commission of acts of destruction; propensity to destroy. • (n.) The quality of destroying or ruining.
De·struc'tive·ness noun 1. The quality of destroying or ruining. Prynne. 2. (Phren.) The faculty supposed to impel to the commission of acts of destruction; propensity to destroy. 
[n] - the quality of causing destruction
noun the quality of causing destruction
the quality of causing destruction