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[dee-reyl] /diˈreɪl/
verb (used with object)
to cause (a train, streetcar, etc.) to run off the rails of a track.
to cause to fail or become deflected from a purpose; reduce or delay the chances for success or development of:
Being drafted into the army derailed his career for two years.
verb (used without object)
(of a train, streetcar, etc.) to run off the rails of a track.
to become derailed; go astray.
a track device for derailing rolling stock in an emergency.
1840-50; < French dérailler, equivalent to dé- dis-1 + -railler, verbal derivative of rail rail1 (< E) Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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Examples from the web for derailed
  • The insider was profoundly disappointed and left to wonder what had derailed his candidacy.
  • For example, your entire digital humanities project could be derailed by a server failure.
  • Not that quick, and obviously could be derailed by any number of factors, but well within the range of many animals and plants.
  • The duo worked with several major labels over the years, but those deals all derailed.
  • But don't expect his nomination to be derailed by it.
  • Not to have done so would have derailed any hopes he might nurture of running for a second presidential term.
  • Otherwise, the more extreme contenders have all been derailed before they could pose much of a threat.
  • The state agency responsible for indigent defense has run out of money, and other cases are at risk of being delayed or derailed.
  • After that early career high, he seems to have been derailed.
  • Both teams faced challenges that could have derailed less determined crews, but they found ways to surmount them.
British Dictionary definitions for derailed


to go or cause to go off the rails, as a train, tram, etc
(mainly US) Also called derailer. a device designed to make rolling stock or locomotives leave the rails to avoid a collision or accident
Derived Forms
derailment, noun
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
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Word Origin and History for derailed



1850, in both transitive and intransitive senses, from French dérailler "to go off the rails," from de- (see de-) + railler (see rail (n.1)). In general use first in U.S. Related: Derailed; derailing.

Online Etymology Dictionary, © 2010 Douglas Harper
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Slang definitions & phrases for derailed



To throw off the proper course; wreck: He managed to derail the proposal just before Christmas

[1950s+; The source term, ''To leave or cause a car or engine to leave the railroad tracks,'' was adopted fr French by 1850]

The Dictionary of American Slang, Fourth Edition by Barbara Ann Kipfer, PhD. and Robert L. Chapman, Ph.D.
Copyright (C) 2007 by HarperCollins Publishers.
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