will not wash

will not wash

Will not be accepted or believed as true. That kind of excuse may have worked in high school, but it will not 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 will not wash in these parts—these people want straight answers.
See also: not, wash, will

something won't wash

If an explanation or idea won't wash, it will not be believed or accepted. Mr Aitken might try some such explanation if and when he returns. It won't wash. It won't wash to claim that what we eat is purely a matter of personal responsibility.
See also: something, wash