The crossword solution for the term 'BITE PERSISTENTLY' is GNAW, which is a four-letter word. GNAW is an action verb that means to chew on something continuously and with determination. It is often used to describe the behavior of animals such as rodents, who will GNAW on objects in order to get to food or to create a shelter. In humans, gnawing can be used to describe the persistent biting of nails or other objects.