acute vs subacute

acute is a noun but subacute is not a noun.

Word	Noun	Adjective	Verb	Adverb
acute	Yes	Yes	No	No
subacute	No	Yes	No	No

acute (noun)	subacute (noun)
a mark placed above a vowel to indicate pronunciation

acute (adjective)	subacute (adjective)
having or experiencing a rapid onset and short but severe course	less than acute; relating to a disease present in a person with no symptoms of it
of an angle; less than 90 degrees
of critical importance and consequence
having or demonstrating ability to recognize or draw fine distinctions
ending in a sharp point
extremely sharp or severe