won't wash

not wash

To not be accepted or believed. That kind of excuse may have worked in high school, but it doesn't wash with me. The deadline for the paper is tomorrow, no extensions. He may be able to skirt the issue in some regions, but that approach won't wash in these parts—these people want straight answers.
See also: not, wash
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

won't wash

Will not stand up to examination, is unconvincing, will not work, as in That excuse about your sick aunt just won't wash. This expression originally alluded to a fabric that would not stand up to washing but by the late 1800s was used figuratively for other kinds of failure.
See also: wash
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.

won't wash

will not be believed or accepted. informal
1998 New Scientist In the end, however, this argument won't wash.
See also: wash
Farlex Partner Idioms Dictionary © Farlex 2017

something won’t/doesn’t ˈwash (with somebody)

used to say that somebody’s explanation, excuse, etc. is not valid or that you/somebody else will not accept it: That excuse simply won’t wash with me.
See also: something, wash
Farlex Partner Idioms Dictionary © Farlex 2017
See also:
References in classic literature ?
But it won't wash historically, because Dreyfus's document (if it was his document) was literally correct."
"That won't wash," said the doctor aside to the priest.
What works for Boris in England and it seems in Wales just won't wash up there.
But that won't wash with a lot of supporters because they have had more than enough of the current regime.
Hand wringing, wearing rosaries or swinging incense won't wash with the man in the street.
But sharing your dirty laundry with the world won't wash.
'I won't wash this because this is some sort of memorabilia that says I gave it my all for La Salle.'
IT WON'T WASH In her second stint, in 2009, Katie Price kept being chosen for Bushtucker Trials
The down is water-repellent and stays dry 10 times longer than untreated down.The water repellency won't wash out and is free of harmful fluorocarbons.
But, according to Lacson, ''we can, but only if my family will eat only once a day, won't brush our teeth nor take a bath, walk every day to and from our place of work but avoid perspiring so we won't wash our clothes.''
That sorry I am late for work excuse won't wash. Don't worry.
AM Simon Thomas' excuse, reported on BBC Wales Politics, that Plaid's conduct of disciplinary matters is "appalling" won't wash. Plaid does have a procedure.
And as the British government appeared to be at loggerheads with EU officials, she said: "This cavalier approach just won't wash in a situation as complex as this, and it's also totally unacceptable when people's jobs and livelihoods are at risk."
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