endeavour vs endeavor

endeavour and endeavor both are nouns.

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

As nouns, endeavour and endeavor are synonyms defined as:

endeavour and endeavor: earnest and conscientious activity intended to do or accomplish something

Other synonyms of endeavour include attempt, effort, try.

As nouns, endeavour and endeavor are synonyms defined as:

endeavour and endeavor: a purposeful or industrious undertaking (especially one that requires effort or boldness)

Other synonyms of endeavour include enterprise.

As verbs, endeavour and endeavor are synonyms defined as:

Other synonyms of endeavour include strive.

endeavour (noun)	endeavor (noun)
earnest and conscientious activity intended to do or accomplish something	earnest and conscientious activity intended to do or accomplish something
a purposeful or industrious undertaking (especially one that requires effort or boldness)	a purposeful or industrious undertaking (especially one that requires effort or boldness)

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