precautional vs preventive

precautional is not a noun while preventive is a noun.

Word	Noun	Adjective	Verb	Adverb
precautional	No	Yes	No	No
preventive	Yes	Yes	No	No

precautional (noun)	preventive (noun)
	remedy that prevents or slows the course of an illness or disease
	an agent or device intended to prevent conception
	any obstruction that impedes or is burdensome

precautional (adjective)	preventive (adjective)
taken in advance to protect against possible danger or failure	tending to prevent or hinder
	preventing or contributing to the prevention of disease