madcap

American  

[mad-kap] / ˈmædˌkæp /

adjective

1. wildly or heedlessly impulsive; reckless; rash.

   a madcap scheme.

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noun

1. a madcap person.

madcap British  

/ ˈmædˌkæp /

adjective

1. impulsive, reckless, or lively

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noun

1. an impulsive, reckless, or lively person

Etymology

Origin of madcap

First recorded in 1580–90; mad + cap ¹

Explanation

Madcap things are done in a foolish, rash, or impulsive way, without planning or thought. Your madcap adventure might include a spur-of-the-moment bus ride to a nearby city without enough money in your pocket to buy lunch. The adjective madcap, which can simply mean "impetuous," can also have a sense of "funny and eccentric." A movie that's described as a madcap comedy will probably be full of broad slapstick and laugh-out-loud physical humor. Madcap, dating from the 16th century, originally meant "lunatic" or "crazy person," from the "head" sense of cap — in other words, a madcap was a "crazy head."

Example Sentences

In a staggering contest of 13 tries and 90 points, Gregor Townsend's men were astonishing in every way until a madcap endgame that saw France run in a battery of tries.

From BBC • Mar. 7, 2026

The Warriors had led until the end of the third quarter, before a madcap finish saw 12 lead changes, with regular time ending 101-101.

From Barron's • Mar. 6, 2026

But several of those madcap ideas flummoxed fans—Carlin pointed to the 1972 single “Mary Had a Little Lamb,” which was inspired by the nursery rhyme.

From The Wall Street Journal • Feb. 27, 2026

Adapted from Donald E. Westlake’s 1997 novel, appropriately titled “The Ax,” Park’s film immediately acknowledges that the madcap journey viewers are about to see is cyclical, not special.

From Salon • Oct. 7, 2025

Color was splashed through the woods as if it had been thrown about by some madcap wastrel who spilled out, during the weeks of one brief autumn, beauty enough to last for years.

From "Across Five Aprils" by Irene Hunt