pre-emptive vs preempt

pre-emptive is not a noun while preempt is a noun.

Word	Noun	Adjective	Verb	Adverb
pre-emptive	No	Yes	No	No
preempt	Yes	No	Yes	No

pre-emptive (noun)	preempt (noun)
	a high bid that is intended to prevent the opposing players from bidding

pre-emptive (adjective)	preempt (adjective)
designed or having the power to deter or prevent an anticipated situation or occurrence

pre-emptive (verb)	preempt (verb)
	acquire for oneself before others can do so
	make a preemptive bid in the game of bridge
	gain possession of by prior right or opportunity, especially so as to obtain the right to buy (land)
	take the place of or have precedence over