purposeful vs earnest

purposeful is not a noun while earnest is a noun.

Word	Noun	Adjective	Verb	Adverb
purposeful	No	Yes	No	No
earnest	Yes	Yes	No	No

purposeful (noun)	earnest (noun)
	something of value given by one person to another to bind a contract

purposeful (adjective)	earnest (adjective)
serving as or indicating the existence of a purpose or goal	not distracted by anything unrelated to the goal
having meaning through having an aim	characterized by a firm and humorless belief in the validity of your opinions
	sincerely earnest