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headlong

American  
[hed-lawng, -long] / ˈhɛdˌlɔŋ, -ˌlɒŋ /

adverb

  1. with the head foremost; headfirst.

    to plunge headlong into the water.

  2. without delay; hastily.

    to plunge headlong into work.

  3. without deliberation; rashly.

    to rush headlong into battle.

adjective

  1. undertaken quickly and suddenly; made precipitately; hasty.

    a headlong flight.

  2. rash; impetuous.

    a headlong denunciation.

  3. done or going with the head foremost.

    a headlong dive into the pool.
headlong British  
/ ˈhɛdˌlɒŋ /

adverb

  1. with the head foremost; headfirst

  2. with great haste

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

adjective

  1. archaic (of slopes, etc) very steep; precipitous

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Other Word Forms

  • headlongness noun

Etymology

Origin of headlong

First recorded in 1350–1400; Middle English hedlong, earlier hedling; head, -ling 2

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

“It looks like they’re running headlong into a brick wall,” Valatsas said.

From The Wall Street Journal • Jan. 21, 2026

Saturday's Anfield horror show at the hands of Nottingham Forest was a headlong fall into the abyss.

From BBC • Nov. 22, 2025

Ireland hosts one of the world's fast-growing clusters of data centres, but is running headlong into the difficult consequences.

From Barron's • Nov. 19, 2025

A selloff that thrashed U.S. stocks and extended into international markets ran headlong Friday into one of the most powerful forces in America’s multiyear rally.

From The Wall Street Journal • Nov. 14, 2025

Kicking off her buckled shoes and dropping the woolen cloak, she plunged headlong over the side of the boat.

From "The Witch of Blackbird Pond" by Elizabeth George Speare

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.