extensor muscle vs extensor

extensor muscle and extensor both are nouns.

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

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

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

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