From Wiktionary, the free dictionary
oil and water pl (plural only)
- (idiomatic) Two things which are incapable of mixing or coexisting harmoniously with each other.
1982, Winston Graham, The Miller's Dance[1], Pan Books, published 2008, →ISBN:We are oil and water. There are few things he and I agree on but I believe we would agree on this.
2009, Brian Schofield, Selling Your Father's Bones: America's 140-Year War against the Nez Perce Tribe, Simon & Schuster, →ISBN, page 31:[…] second, that the white and red man were oil and water, incapable of safely sharing a landscape.
2011, Loretta M. Siani, The Alchemy of Prayer: How It Began and Why It Is the Medium of Miracles, iUniverse, →ISBN, page 47:Forgiveness and making bargains are oil and water. They don't mix.
- For more quotations using this term, see Citations:oil and water.