nastiness

Concise Oxford English Dictionary © 2008 Oxford University Press:
nasty/ˈnɑːsti/

▶adjective (nastier, nastiest)

• 1 highly unpleasant or repugnant.

• 2 unpleasant or spiteful in behaviour.

  ■ annoying or unwelcome.

• 3 physically or mentally damaging or harmful.

▶noun (pl. nasties) informal a nasty person or thing.

– derivatives
nastily adverb,
nastiness noun.

– origin ME: of unknown origin.