OK vs sanction

OK and sanction both are nouns.

Word	Noun	Adjective	Verb	Adverb
OK	Yes	No	No	Yes
sanction	Yes	No	Yes	No

As nouns, sanction is a hypernym of OK; that is, sanction is a word with a broader meaning than OK:

Other hypernyms of OK include countenance, endorsement, imprimatur, indorsement, warrant.

OK (noun)	sanction (noun)
an endorsement	the act of final authorization
a state in south central United States	a mechanism of social control for enforcing a society's standards
	official permission or approval
	formal and explicit approval

OK (verb)	sanction (verb)
	give sanction to
	give religious sanction to, such as through an oath
	give authority or permission to

OK (adverb)	sanction (adverb)
an expression of agreement normally occurring at the beginning of a sentence