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

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

Dubbed in different languages, the show captured children's hearts with its madcap battles.

From Barron's • Nov. 14, 2025

Here, Sophocles’ “Oedipus the King” and Elvis, the King of Rock ’n’ Roll, are brought together for an equally madcap if less artfully composed mashup.

From Los Angeles Times • Sep. 5, 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