hamster vs gnawer

hamster and gnawer both are nouns.

Word	Noun	Adjective	Verb	Adverb
hamster	Yes	No	No	No
gnawer	Yes	No	No	No

As nouns, gnawer is a hypernym of hamster; that is, gnawer is a word with a broader meaning than hamster:

hamster: short-tailed Old World burrowing rodent with large cheek pouches
gnawer: relatively small placental mammals having a single pair of constantly growing incisor teeth specialized for gnawing

Other hypernyms of hamster include rodent.

hamster (noun)	gnawer (noun)
short-tailed Old World burrowing rodent with large cheek pouches	relatively small placental mammals having a single pair of constantly growing incisor teeth specialized for gnawing