The quality or state of being destructive; the capacity or tendency to cause destruction or damage.
From 'destructive' plus '-ness' (a suffix that forms abstract nouns expressing a quality or state). This common formation allows adjectives to become nouns representing their essential quality.
Phrenologists once theorized that 'destructiveness' was a localized brain capacity, and they even claimed to find a 'destruction bump' on the skull—it was pseudoscience, but it shows how deeply humans have tried to understand our capacity for harm.
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