purchase vs choose

purchase is a noun but choose is not a noun.

Word	Noun	Adjective	Verb	Adverb
purchase	Yes	No	Yes	No
choose	No	No	Yes	No

purchase (noun)	choose (noun)
the acquisition of something for payment
the mechanical advantage gained by being in a position to use a lever
a means of exerting influence or gaining advantage
something acquired by purchase

purchase (verb)	choose (verb)
obtain by purchase; acquire by means of a financial transaction	pick out, select, or choose from a number of alternatives
	see fit or proper to act in a certain way; decide to act in a certain way
	select as an alternative over another