muskrat vs muskrat fur

muskrat and muskrat fur both are nouns.

Word	Noun	Adjective	Verb	Adverb
muskrat	Yes	No	No	No
muskrat fur	Yes	No	No	No

As nouns, muskrat and muskrat fur are synonyms defined as:

muskrat (noun)	muskrat fur (noun)
beaver-like aquatic rodent of North America with dark glossy brown fur	the brown fur of a muskrat
the brown fur of a muskrat