outpost vs frontier settlement

outpost and frontier settlement both are nouns.

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

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

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

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