April fool

April fool (plural April fools)

1. A person subjected to a practical joke on April Fools' Day.
   • 1785, Francis Grose, A Classical Dictionary of the Vulgar Tongue, p 4:

     APRIL FOOL, Any one imposed on, or sent on a bootless errand on the first of April, on which day it is the custom among the lower people, children, and servants, by dropping empty papers carefully doubled up, sending persons on absurd messages, and such like contrivances, to impose on every one they can, and then to salute them with the title of April-fool.

2. A practical joke played on April Fools' Day.
   • 2012, Benedict le Vay, Ben Le Vay's Eccentric Britain, page 14:

     The best April fool ever perpetrated was 1 April 1698 and made a laughing stock of the gentry of London, great numbers of whom turned up in their carriages and finery at the Tower of London to 'see the lions being washed' as instructed on their gilt-edged invitation cards.

• Often used as an exclamation upon revealing the joke.

• (person): gowk (Scottish)