(lit. water-hating) The degree to which a molecule is insoluble in water, and hence is soluble in lipids. If a molecule lacking polar groups is placed in water, it will be entropically driven to finding a hyrdophobic environment (such as the interior of a protein or a membrane).
Resistance to wetting exhibited by some soils, also called water repellency. The phenomenon may occur naturally or may be fire-induced. It may be determined by water drop penetration time, equilibrium liquid-contact angles, solid-air surface tension indices, or the characterization of dynamic wetting angles during infiltration.