extensor vs extensor muscle

extensor and extensor muscle both are nouns.

Word	Noun	Adjective	Verb	Adverb
extensor	Yes	No	No	No
extensor muscle	Yes	No	No	No

As nouns, extensor and extensor muscle are synonyms defined as:

extensor and extensor muscle: a skeletal muscle whose contraction extends or stretches a body part

extensor (noun)	extensor muscle (noun)
a skeletal muscle whose contraction extends or stretches a body part	a skeletal muscle whose contraction extends or stretches a body part