tendon vs sinew

tendon and sinew both are nouns.

Word	Noun	Adjective	Verb	Adverb
tendon	Yes	No	No	No
sinew	Yes	No	No	No

As nouns, tendon and sinew are synonyms defined as:

tendon and sinew: a cord or band of inelastic tissue connecting a muscle with its bony attachment

tendon (noun)	sinew (noun)
a cord or band of inelastic tissue connecting a muscle with its bony attachment	possessing muscular strength
	a cord or band of inelastic tissue connecting a muscle with its bony attachment