Which term describes substances that are repelled by water?

The term that describes substances that are repelled by water is hydrophobic. This characteristic refers to molecules or groups that do not interact favorably with water and tend to avoid it. Hydrophobic substances are typically nonpolar and do not form hydrogen bonds with water molecules, which contributes to their inability to dissolve in aqueous environments. These substances include oils and fats, which are commonly recognized as hydrophobic due to their molecular structure.

In contrast, hydrophilic substances are attracted to water and can easily dissolve in it, often because they are polar or ionic. Amphipathic compounds contain both hydrophilic and hydrophobic parts, such as phospholipids, which can interact with both water and fat molecules. Lipophilic substances, while sometimes used interchangeably with hydrophobic, specifically refer to a preference for lipid environments rather than a general aversion to water. Thus, hydrophobic is the most accurate term for substances that are repelled by water.