flexor vs skeletal muscle

flexor and skeletal muscle both are nouns.

Word	Noun	Adjective	Verb	Adverb
flexor	Yes	No	No	No
skeletal muscle	Yes	No	No	No

As nouns, skeletal muscle is a hypernym of flexor; that is, skeletal muscle is a word with a broader meaning than flexor:

flexor: a skeletal muscle whose contraction bends a joint
skeletal muscle: a muscle that is connected at either or both ends to a bone and so move parts of the skeleton; a muscle that is characterized by transverse stripes

Other hypernyms of flexor include striated muscle.

flexor (noun)	skeletal muscle (noun)
a skeletal muscle whose contraction bends a joint	a muscle that is connected at either or both ends to a bone and so move parts of the skeleton; a muscle that is characterized by transverse stripes