油あぶらに水みず

Meanings

incompatible; like oil and water

Idiomatic expression describing two things or people that do not mix well, just as oil and water separate. Often used in the pattern 〜は油に水だ or 〜と〜は油に水のようだ.

彼かれと彼かの女じょは油あぶらに水みずで、いつも喧けん嘩かばかりしている。
He and she are like oil and water; they're always fighting.
自じ由ゆう奔ほん放ぽうな彼かれと几き帳ちょう面めんな彼かの女じょは、まさに油あぶらに水みずだ。
The free-spirited him and the meticulous her are truly incompatible.