critical vs acute

critical is not a noun while acute is a noun.

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

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

critical (adjective)	acute (adjective)
marked by a tendency to find and call attention to errors and flaws	having or experiencing a rapid onset and short but severe course
characterized by careful evaluation and judgment	of an angle; less than 90 degrees
being in or verging on a state of crisis or emergency	of critical importance and consequence
at or of a point at which a property or phenomenon suffers an abrupt change especially having enough mass to sustain a chain reaction	having or demonstrating ability to recognize or draw fine distinctions
of or involving or characteristic of critics or criticism	ending in a sharp point
forming or having the nature of a turning point or crisis	extremely sharp or severe
urgently needed; absolutely necessary