frontier settlement vs outpost

frontier settlement and outpost both are nouns.

Word	Noun	Adjective	Verb	Adverb
frontier settlement	Yes	No	No	No
outpost	Yes	No	No	No

As nouns, frontier settlement and outpost are synonyms defined as:

frontier settlement and outpost: a settlement on the frontier of civilization

frontier settlement (noun)	outpost (noun)
a settlement on the frontier of civilization	a military post stationed at a distance from the main body of troops
	a settlement on the frontier of civilization
	a station in a remote or sparsely populated location