nounNorth American informal
A mad or eccentric person.
More example sentences
- Neither of them are kooks, they've simply been lied to by the people who are in charge.
- I worry just as much, however, about the kooks out there who think that now is the time to plant a bomb.
- The only people who cite the Columbia study are kooks and religious zealots.
1960s: probably from cuckoo.
Definition of kook in:
- The US English dictionary