visa vs sanction

visa and sanction both are nouns.

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

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

visa: an endorsement made in a passport that allows the bearer to enter the country issuing it
sanction: formal and explicit approval

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

As verbs, sanction is a hypernym of visa; that is, sanction is a word with a broader meaning than visa:

Other hypernyms of visa include approve, O.K., okay.

visa (noun)	sanction (noun)
an endorsement made in a passport that allows the bearer to enter the country issuing it	the act of final authorization
	a mechanism of social control for enforcing a society's standards
	official permission or approval
	formal and explicit approval

visa (verb)	sanction (verb)
provide (a passport) with a visa	give sanction to
approve officially	give religious sanction to, such as through an oath
	give authority or permission to