Main Entry: de·rail

Pronunciation: \di-ˈrāl, dē-\

Function: verb

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

Date: 1850

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

— de·rail·ment \-mənt\ noun