Nouns

(n)bestthe supreme effort one can make“they did their best”
(n)best, topperthe person who is most outstanding or excellent; someone who tops all others“he could beat the best of them”

Verbs

(v)outdo, outflank, trump, best, scoopget the better of“the goal was to best the competition”

Adjectives

(a)best(superlative of `good') having the most positive qualities“the best film of the year”, “the best solution”, “the best time for planting”, “wore his best suit”
(s)better, best(comparative and superlative of `well') wiser or more advantageous and hence advisable“it would be better to speak to him”, “the White House thought it best not to respond”

Adverbs

(r)bestin a most excellent way or manner“he played best after a couple of martinis”
(r)bestit would be sensible“you'd best stay at home”
(r)better, bestfrom a position of superiority or authority“father knows best”, “I know better.”