Definition
To try to do something that is very difficult or impossible to achieve, often leading to frustration and annoyance.
I tried to convince him to change his mind, but it was like banging my head against a brick wall; he wouldn't listen.
Arguing with them about this issue is like banging your head against a brick wall; it's a complete waste of time.
Trying to get her to admit her mistake is like banging your head against a brick wall.