outer vs external

outer is not a noun while external is a noun.

Word	Noun	Adjective	Verb	Adverb
outer	No	Yes	No	No
external	Yes	Yes	No	No

outer (noun)	external (noun)
	outward features

outer (adjective)	external (adjective)
being on the outside or further from a center	happening or arising or located outside or beyond some limits or especially surface
being on or toward the outside of the body	coming from the outside
located outside	from or between other countries
	purely outward or superficial