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breakneck

American  
[breyk-nek] / ˈbreɪkˌnɛk /

adjective

  1. reckless or dangerous, especially because of excessive speed; hazardous.

    He raced through the streets at breakneck speed.
breakneck British  
/ ˈbreɪkˌnɛk /

adjective

  1. (prenominal) (of speed, pace, etc) excessive and dangerous

"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

Etymology

Origin of breakneck

First recorded in 1555–65; break + neck

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.