lost cause

lost cause idiom
A hopeless undertaking, as in Trying to get him to quit smoking is a lost cause. In the 1860s this expression was widely used to describe the Confederacy. [Mid-1800s] Also see losing battle.

The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

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