waste one's breath

waste (one's) breath

To talk of, discuss, or say things that are likely to be ignored or are in vain. Don't bother trying to change my mind about this, you're wasting your breath! It looks like I wasted my breath trying to pitch my idea to the board of directors.
See also: breath, waste
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

waste one's breath

Speak in vain (because no one agrees), as in Don't waste your breath complaining to the supervisor-it won't help. This notion was first recorded about 1400 as wasting words. The exact idiom was first recorded in 1667. Also see save one's breath.
See also: breath, waste
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.

waste one's breath, to

To talk in vain, because no one will listen. The idea that breath is something that can be saved or wasted dates from the sixteenth century (see also save your breath). Tennyson used the term in “In Memoriam” (1850): “I trust I have not wasted breath.”
See also: waste
The Dictionary of Clichés by Christine Ammer Copyright © 2013 by Christine Ammer
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References in periodicals archive ?
No need to waste one's breath explaining to them that Whitman's "Children of Adam" is as heteroerotic as "Calamus" is homo-: they're convinced that Whitman spent his waking hours prowling the streets of Washington and Camden in search of day laborers for a roll in the hay.