Definition of frightfulness in US English:

frightfulness

noun

British
  • See frightful

    • ‘They saw at once its beauty and its frightfulness.’
    • ‘In the Imperial proclamation the fact that certain ‘frightful’ things have been done is admitted, and justified on the ground of their frightfulness.’
    • ‘The fact that they are increasingly referred to as ‘events’ underlines their frightfulness.’
    • ‘Nor can it outweigh the sporadic frightfulness of pain and despair that occurs every second of every day.’
    • ‘But most important, Schatzberg and company have made The Panic in Needle Park an occasion for the American public to meditate upon the frightfulness of heroin addiction.’