A rodent or other similar type of animal that gnaws.(noun)
Wiktionary.org : Text is available under the Creative Commons Attribution-ShareAlike License
Use "gnawer" in a sentence
"(A delightful true story of food, Paris, and the fulfillment of a lifelong dream) rongeur (ron-zhay) noun, masculine rodent, gnawer"
"Crumb-snatcher am I called, and I am the son of Bread-nibbler — he was my stout-hearted father — and my mother was Quern-licker, the daughter of Ham-gnawer the king: she bare me in the mouse-hole and nourished me with food, figs and nuts and dainties of all kinds."
"Among them were the teeth of a gnawer, equalling in size and closely resembling those of the Capybara, whose habits have been described; and therefore, probably, an aquatic animal."