striving vs endeavor

striving and endeavor both are nouns.

Word	Noun	Adjective	Verb	Adverb
striving	Yes	No	No	No
endeavor	Yes	No	Yes	No

As nouns, endeavor is a hypernym of striving; that is, endeavor is a word with a broader meaning than striving:

striving: an effortful attempt to attain a goal
endeavor: earnest and conscientious activity intended to do or accomplish something

Other hypernyms of striving include attempt, effort, endeavour, try.

striving (noun)	endeavor (noun)
an effortful attempt to attain a goal	earnest and conscientious activity intended to do or accomplish something
	a purposeful or industrious undertaking (especially one that requires effort or boldness)

striving (verb)	endeavor (verb)
	attempt by employing effort