Instead of mixing, some liquids dissolve in oil. These are also nonpolar liquids, like:
* Other oils: Vegetable oils, mineral oil, etc.
* Solvents: Acetone, toluene, kerosene, gasoline.
* Fats: Butter, lard, etc.
Water and oil don't mix because the water molecules are attracted to each other (hydrogen bonds) and "push" the oil molecules away.
Important Note: Some substances can act as emulsifiers, which help to temporarily suspend tiny droplets of oil within water, creating a mixture that appears mixed but is actually a temporary suspension. Examples of emulsifiers include soap and egg yolks.