beat vs knock out

beat is a noun but knock out is not a noun.

Word	Noun	Adjective	Verb	Adverb
beat	Yes	Yes	Yes	No
knock out	No	No	Yes	No

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

beat: give a beating to; subject to a beating, either as a punishment or as an act of aggression
knock out: knock unconscious or senseless

beat (noun)	knock out (noun)
the act of beating to windward; sailing as close as possible to the direction from which the wind is blowing
a stroke or blow
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)	knock out (adjective)
very tired

beat (verb)	knock out (verb)
wear out completely	destroy or break forcefully
be a mystery or bewildering to	eliminate
come out better in a competition, race, or conflict	empty (as of tobacco) by knocking out
beat through cleverness and wit	knock unconscious or senseless
hit repeatedly	overwhelm with admiration
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