preemptive vs preventive

preemptive is not a noun while preventive is a noun.

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

preemptive (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

preemptive (adjective)	preventive (adjective)
designed or having the power to deter or prevent an anticipated situation or occurrence	tending to prevent or hinder
	preventing or contributing to the prevention of disease