Definition of kookiness in US English:

kookiness

noun

informal
  • See kooky

    • ‘Sara's kookiness charms him, understandably, but what's she getting out of it?’
    • ‘Imbruglia's voice is still undeniably sweet on the ears, combining the assuredness of Madonna with the cute kookiness of Cyndi Lauper.’
    • ‘A little kookiness is fine.’
    • ‘Kate Hudson is unexpectedly subdued as Caroline, demonstrating none of the slightly manic kookiness that she normally trades in.’
    • ‘The kookiness comes over as detachment or other-worldliness.’