best vs vanquish

best is a noun but vanquish is not a noun.

Word	Noun	Adjective	Verb	Adverb
best	Yes	Yes	Yes	Yes
vanquish	No	No	Yes	No

As verbs, vanquish is a hypernym of best; that is, vanquish is a word with a broader meaning than best:

Other hypernyms of best include beat, beat out, crush, shell, trounce.

best (noun)	vanquish (noun)
the supreme effort one can make
the person who is most outstanding or excellent; someone who tops all others

best (adjective)	vanquish (adjective)
(superlative of `good') having the most positive qualities
(comparative and superlative of `well') wiser or more advantageous and hence advisable

best (verb)	vanquish (verb)
get the better of	come out better in a competition, race, or conflict

best (adverb)	vanquish (adverb)
it would be sensible
in a most excellent way or manner
from a position of superiority or authority