whistle in the wind

whistle in the wind

To engage in a fruitless or hopeless task; to try to produce an effect or influence something with no real hope of succeeding. We all know that he's guilty, but if we can't get concrete evidence, we're just going to be whistling in the wind. He mocked the senators ahead of the investigation, saying they were just whistling in the wind.
See also: whistle, wind

whistle in the wind

try unsuccessfully to influence something that cannot be changed.
See also: whistle, wind