okay vs endorse

okay is a noun but endorse is not a noun.

Word	Noun	Adjective	Verb	Adverb
okay	Yes	Yes	Yes	Yes
endorse	No	No	Yes	No

As verbs, endorse is a hyponym of okay; that is, endorse is a word with a more specific, narrower meaning than okay:

Other hyponyms of okay include sanctify, sanction, visa, back, indorse, plump for, plunk for, support, confirm, greenlight.

okay (noun)	endorse (noun)
an endorsement

okay (adjective)	endorse (adjective)
being satisfactory or in satisfactory condition

okay (verb)	endorse (verb)
give sanction to	sign as evidence of legal transfer
	be behind; approve of
	guarantee as meeting a certain standard
	give support or one's approval to

okay (adverb)	endorse (adverb)
in a satisfactory or adequate manner