invasion vs intrusion

invasion and intrusion both are nouns.

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

As nouns, invasion and intrusion are synonyms defined as:

Other synonyms of invasion include encroachment.

invasion (noun)	intrusion (noun)
the act of invading; the act of an army that invades for conquest or plunder	entry to another's property without right or permission
any entry into an area not previously occupied	entrance by force or without permission or welcome
(pathology) the spread of pathogenic microorganisms or malignant cells to new sites in the body	any entry into an area not previously occupied
	rock produced by an intrusive process
	the forcing of molten rock into fissures or between strata of an earlier rock formation