international vs external

international is not a noun while external is a noun.

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

As adjectives, international and external are synonyms defined as:

Other synonyms of international include outside.

international (noun)	external (noun)
	outward features

international (adjective)	external (adjective)
concerning or belonging to all or at least two or more nations	happening or arising or located outside or beyond some limits or especially surface
from or between other countries	coming from the outside
	from or between other countries
	purely outward or superficial