knock (one's) head against a (brick) wall

(redirected from knocking their heads against a brick wall)

knock (one's) head against a (brick) wall

To attempt continuously and fruitlessly to accomplish some task or achieve some goal that is or seems ultimately hopeless. I feel like I've been knocking my head against a brick wall trying to understand this math equation. Some people are never going to agree with you on this, so it's no use knocking your head against a wall trying to convince everyone.
See also: head, knock, wall
References in periodicals archive ?
Lisa Young, 23, and Scott Little, 26, from Sheffield, felt they were knocking their heads against a brick wall when they tried to raise a mortgage.