April fool

Noun

April fool (plural April fools)

1. A person subjected to a practical joke on April Fools' Day.
   • 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...1785, Francis Grose, A Classical Dictionary of the Vulgar Tongue,, page 4
2. A practical joke played on April Fools' Day.
   • 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.2012, Benedict le Vay, Ben Le Vay's Eccentric Britain, page 14