What does it mean to bite at or chew on something to erode it?

The term that best captures the action of biting at or chewing on something to erode it is "gnaw." This word implies a repetitive action of biting or chewing, often associated with how animals might eat away at something gradually. It's commonly used to describe the process of reducing the size or integrity of an object over time, such as how a rodent might gnaw on wood or how certain behaviors can gradually erode a person's resolve or spirit.

The other terms do not convey the same meaning. "Glimpse" refers to a brief or fleeting view, which has no relation to erosion. "Groom" typically involves cleaning or maintaining appearance, not the act of biting or eroding. "Gorge" usually means to eat greedily or excessively, which also does not align with the concept of chewing as a method of erosion. Thus, "gnaw" is the clear choice that defines the action in question.