invade vs invasion

invade is not a noun while invasion is a noun.

Word	Noun	Adjective	Verb	Adverb
invade	No	No	Yes	No
invasion	Yes	No	No	No

invade (noun)	invasion (noun)
	the act of invading; the act of an army that invades for conquest or plunder
	any entry into an area not previously occupied
	(pathology) the spread of pathogenic microorganisms or malignant cells to new sites in the body

invade (verb)	invasion (verb)
march aggressively into another's territory by military force for the purposes of conquest and occupation
penetrate or assault, in a harmful or injurious way
to intrude upon, infringe, encroach on, violate
occupy in large numbers or live on a host