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

With a major role in Josh Safdie’s madcap ping-pong riot, “Marty Supreme,” Paltrow is rounding out the year with a bang, earning her last laugh against gossip hounds and Goop critics.

From Salon • Dec. 22, 2025

The madcap zeal that Madame Pernelle brings to the stage only intermittently returns to the production.

From The Wall Street Journal • Dec. 17, 2025

I think of her madcap, joyful dresses, of her dust-covered bedroom.

From "The Cruel Prince" by Holly Black