gnaw

verbs

bite or chew on with the teeth
"gnaw an old cracker"
gnaw
is derived from
gnawer
is a type of (narrower)
chew (food); to bite and grind with the teeth
"He jawed his bubble gum"; "Chew your food and don't swallow it!"; "The cows were masticating the grass"
chew, jaw, manducate, masticate
is a type of (narrower)
to grip, cut off, or tear with or as if with the teeth or jaws
"Gunny invariably tried to bite her"
bite, seize with teeth
become ground down or deteriorate
"Her confidence eroded"
eat at, erode, gnaw, gnaw at, wear away