Added 9 October 2026 kook /kuːk/ noun Categories: PeopleRare Words noun ! Definition from WordNet 3.1, Princeton University. Pronunciation from Wiktionary, via Kaikki.org. More about kook at Wordnik → Where our words come from → Someone regarded as eccentric or crazy and standing out from a group. Origin Possibly from cuckoo. From Wiktionary, via Kaikki.org (CC BY-SA) Related Words: wackocrackpotnutcaselunaticmadmanpsychomaniaczany Back to today's word