porcupine vs gnawer

porcupine and gnawer both are nouns.

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

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

porcupine: relatively large rodents with sharp erectile bristles mingled with the fur
gnawer: relatively small placental mammals having a single pair of constantly growing incisor teeth specialized for gnawing

Other hypernyms of porcupine include rodent.

porcupine (noun)	gnawer (noun)
relatively large rodents with sharp erectile bristles mingled with the fur	relatively small placental mammals having a single pair of constantly growing incisor teeth specialized for gnawing