invade vs overrun

invade is not a noun while overrun is a noun.

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

As verbs, overrun is a hyponym of invade; that is, overrun is a word with a more specific, narrower meaning than invade:

invade: march aggressively into another's territory by military force for the purposes of conquest and occupation
overrun: invade in great numbers

Other hyponyms of invade include infest.

As verbs, invade and overrun are synonyms defined as:

Other synonyms of invade include infest.

invade (noun)	overrun (noun)
	too much production or more than expected

invade (verb)	overrun (verb)
march aggressively into another's territory by military force for the purposes of conquest and occupation	run beyond or past
penetrate or assault, in a harmful or injurious way	seize the position of and defeat
to intrude upon, infringe, encroach on, violate	flow or run over (a limit or brim)
occupy in large numbers or live on a host	invade in great numbers
	occupy in large numbers or live on a host