Meaningless / pointless / useless — indicating that something has no value, purpose, or sensible result.
そんな言い訳は説得力がなく、意味がない。
That kind of excuse has no persuasive power and is meaningless.
このデータは壊れていて、分析しても意味がない。
This data is corrupted, so analyzing it would be pointless.
いつまでも過去を悔やんでいても意味がない。前に進もう。
There's no point in regretting the past forever. Let's move forward.
費用対効果が悪く、このプロジェクトは意味がないと判断された。
Because of poor cost-effectiveness, it was judged that this project was pointless.