external vs outer

external is a noun but outer is not a noun.

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

external (noun)	outer (noun)
outward features

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