unconscious vs knocked out

unconscious is a noun but knocked out is not a noun.

Word	Noun	Adjective	Verb	Adverb
unconscious	Yes	Yes	No	No
knocked out	No	Yes	No	No

unconscious (noun)	knocked out (noun)
that part of the mind wherein psychic activity takes place of which the person is unaware

unconscious (adjective)	knocked out (adjective)
not conscious; lacking awareness and the capacity for sensory perception as if asleep or dead	knocked unconscious by a heavy blow
without conscious volition
(followed by `of') not knowing or perceiving