Ill-suited

The best thing in the world for a man is to choose a good wife, the worst being to mistakenly choose an ill-suited one.

Source: tatoeba (58270)

Moreover, because he was handsome, he was ill-suited to working as a teacher in a girls' school.

Source: tatoeba (1819769)

A considerable amount of beet comes from the Clonakilty and Courtmacsherry growing areas to Mallow and if the closure proposals mentioned are implemented this traffic will in future years be thrown on roads ill-suited to such heavy haulage.

Source: wiktionary

an ill-suited married couple

Source: wiktionary