license vs O.K.

license and O.K. both are nouns.

Word	Noun	Adjective	Verb	Adverb
license	Yes	No	Yes	No
O.K.	Yes	No	Yes	Yes

license (noun)	O.K. (noun)
the act of giving a formal (usually written) authorization	an endorsement
a legal document giving official permission to do something
freedom to deviate deliberately from normally applicable rules or practices (especially in behavior or speech)
excessive freedom; lack of due restraint

license (verb)	O.K. (verb)
authorize officially	give sanction to

license (adverb)	O.K. (adverb)
	in a satisfactory or adequate manner