approval vs sanction

approval and sanction both are nouns.

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

As nouns, sanction is a hyponym of approval; that is, sanction is a word with a more specific, narrower meaning than approval:

approval (noun)	sanction (noun)
the formal act of approving	the act of final authorization
a message expressing a favorable opinion	a mechanism of social control for enforcing a society's standards
a feeling of liking something or someone good	official permission or approval
acceptance as satisfactory	formal and explicit approval

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