beat head against the wall

beat (one's) head against a/the wall

To attempt continuously and fruitlessly to accomplish some task or achieve some goal that is or seems ultimately hopeless. Some people are never going to agree with you on this, so it's no use beating your head against a wall trying to convince everyone. I feel like I've been beating my head against the wall trying to understand this math equation.
See also: beat, head, wall
Farlex Dictionary of Idioms. © 2022 Farlex, Inc, all rights reserved.

beat one's head against the wall

 and bang one's head against a brick wall
Fig. to waste one's time trying hard to accomplish something that is completely hopeless. You're wasting your time trying to figure this puzzle out. You're just beating your head against the wall. You're banging your head against a brick wall trying to get that dog to behave properly.
See also: beat, head, wall
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.
See also: