faultfinding vs critical

faultfinding is a noun but critical is not a noun.

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

faultfinding (noun)	critical (noun)
persistent petty and unjustified criticism

faultfinding (adjective)	critical (adjective)
tending to find and call attention to faults	marked by a tendency to find and call attention to errors and flaws
tending to make moral judgments or judgments based on personal opinions	characterized by careful evaluation and judgment
	being in or verging on a state of crisis or emergency
	at or of a point at which a property or phenomenon suffers an abrupt change especially having enough mass to sustain a chain reaction
	of or involving or characteristic of critics or criticism
	forming or having the nature of a turning point or crisis
	urgently needed; absolutely necessary