bay at the moon

To make appeals in vain. Good luck talking to the principal, but I think you'll just be baying at the moon—I doubt you'll get a better grade. Didn't you come home after curfew last night? Yeah, you're baying at the moon if you think Mom's going to let you borrow the car again. Yeah, right, like they're gonna give you a raise after only a year on the job. You're baying at the moon, pal.

bay at the moon

howl at the moon

LITERARY

If you bay at the moon or howl at the moon, you waste your time and energy trying to do something which is impossible or trying to get something which you cannot have. You're looking for the perfect man and he doesn't exist. You're baying at the moon.

bay at the moon

clamour or make an outcry to no effect.

The barking of dogs at a full moon has been a metaphor for futile activity since the mid 17th century.