Gnaw refers to the action of biting or chewing on something persistently, often with the intent to wear it down or break it apart. This behavior is commonly observed in animals like rabbits and rodents, which use their strong teeth to gnaw on food, wood, or other materials to keep their teeth trimmed and healthy. In a broader context, gnaw can also describe a feeling of persistent worry or anxiety that eats away at a person’s peace of mind. For example, someone might feel a gnawing concern about an upcoming exam or a difficult decision, indicating that the worry is constant and troubling.