defeat the purpose

To undermine the act of doing something by having an opposite effect; to nullify.

Japanese Meaning

目的を損ねる、意図に反する結果をもたらして本来の効果を無効にすること

Trying to save money by buying cheap shoes will defeat the purpose if they fall apart after a week.

節約しようとして安い靴を買っても、1週間で壊れてしまえば目的が台無しになる。

Sense（1）

To undermine the act of doing something by having an opposite effect; to nullify.

defeats the purpose

（ present singular third-person ）

defeating the purpose

（ participle present ）

defeated the purpose

（ participle past ）

defeated the purpose

（ past ）