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

The madcap ending was one of several key stories, including:

From BBC • Jun. 7, 2026

The set piece is a daring, madcap, Wes Anderson-esque romp through San Francisco all the way to the Metro Designers factory in China, where worker conditions are grim and hazardous.

From Salon • May 22, 2026

Nancy Lemann, a New Orleans native, has captured her home turf in madcap fiction and reportage.

From The Wall Street Journal • Apr. 24, 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

Letters proposing madcap, unpublished ideas, often accompanied by hand-scribbled figures, were circulated among the members; it was a blog before blogs.

From "The Gene" by Siddhartha Mukherjee