beat vs best

beat and best both are nouns.

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

As verbs, best is a hyponym of beat; that is, best is a word with a more specific, narrower meaning than beat:

beat (noun)	best (noun)
the act of beating to windward; sailing as close as possible to the direction from which the wind is blowing	the supreme effort one can make
a stroke or blow	the person who is most outstanding or excellent; someone who tops all others
a regular rate of repetition
the basic rhythmic unit in a piece of music
(prosody) the accent in a metrical foot of verse
the rhythmic contraction and expansion of the arteries with each beat of the heart
the sound of stroke or blow
a regular route for a sentry or policeman
a member of the beat generation; a nonconformist in dress and behavior
a single pulsation of an oscillation produced by adding two waves of different frequencies; has a frequency equal to the difference between the two oscillations

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

beat (verb)	best (verb)
wear out completely	get the better of
be a mystery or bewildering to
come out better in a competition, race, or conflict
beat through cleverness and wit
hit repeatedly
give a beating to; subject to a beating, either as a punishment or as an act of aggression
stir vigorously
strike (a part of one's own body) repeatedly, as in great emotion or in accompaniment to music
strike (water or bushes) repeatedly to rouse animals for hunting
shape by beating
make by pounding or trampling
produce a rhythm by striking repeatedly
move rhythmically
sail with much tacking or with difficulty
move with a flapping motion
indicate by beating, as with the fingers or drumsticks
move with a thrashing motion
move with or as if with a regular alternating motion
make a rhythmic sound
make a sound like a clock or a timer
glare or strike with great intensity
avoid paying
be superior

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