flexor vs striated muscle

flexor and striated muscle both are nouns.

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

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

flexor: a skeletal muscle whose contraction bends a joint
striated 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 skeletal muscle.

flexor (noun)	striated 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