The phrase "futile effort" means trying very hard to achieve something, but realizing that it is pointless and will not succeed.
Sentences with «futile effort»
As long as we don't make quality signings, all these matches are almost futile efforts. (justarsenal.com)
Second, the sums involved are less massive and therefore can't lure as many young people into a potentially futile effort to launch scientific careers. (sciencemag.org)
Rather than doubling down on such futile efforts, education reformers should seek to expand true accountability by increasing school choice for more families. (educationnext.org)