vantage vs viewpoint

vantage and viewpoint both are nouns.

Word	Noun	Adjective	Verb	Adverb
vantage	Yes	No	No	No
viewpoint	Yes	No	No	No

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

vantage: place or situation affording some advantage (especially a comprehensive view or commanding perspective)
viewpoint: a place from which something can be viewed

Other hyponyms of vantage include vantage point.

vantage (noun)	viewpoint (noun)
the quality of having a superior or more favorable position	a mental position from which things are viewed
place or situation affording some advantage (especially a comprehensive view or commanding perspective)	a place from which something can be viewed