derail

verb

de·​rail di-ˈrāl 

dē-

derailed; derailing; derails

transitive verb

1

: to cause to run off the rails

2

a

: to obstruct the progress of : frustrate

Security problems derailed the tour.

b

: to upset the stability or composure of

… divorce … can seriously derail an employee.

—Joanne Gordon

intransitive verb

: to leave the rails

derailment

di-ˈrāl-mənt 

dē-

noun

Synonyms of derail

• distract
• disturb
• bother
• worry
• alarm
• concern
• unsettle
• agitate
• anger

Examples of derail in a Sentence

The train derailed in heavy snow.

The train was derailed by heavy snow.

Recent Examples on the Web

In June, Israel’s surprise attack on Iran’s military and nuclear facilities derailed a series of ongoing – though foundering – talks between the US and Iran. —Tal Shalev, CNN Money, 10 Feb. 2026

Green Bay’s chances in the NFC North were derailed by an injury to Micah Parsons, but with Parsons leading the defense and Jordan Love leading the offense, Green Bay is a logical contender. —Dan Santaromita, New York Times, 9 Feb. 2026

Or, on the flip side, derail an entire trip due to blisters, fatigue, and sometimes even injury. —Julia Morlino, Travel + Leisure, 9 Feb. 2026

This twist — that 3I/ATLAS' outer layers have been baked by the sun — does not derail our mission. —Paul Sutter, Space.com, 9 Feb. 2026

Word History

Etymology

French dérailler to throw off the track, from dé- de- + rail, from English

First Known Use

1850, in the meaning defined at transitive sense 1

Rhymes for derail

• airmail
• assail
• avail
• bewail
• blackmail
• cattail
• cocktail
• curtail
• detail
• dovetail
• email
• entail

Kids Definition

derail

verb

de·​rail di-ˈrā(ə)l 

: to cause to run off the rails

a train derailed by heavy snow

derailment

-mənt 

noun