emigration vs out-migration

emigration and out-migration both are nouns.

Word	Noun	Adjective	Verb	Adverb
emigration	Yes	No	No	No
out-migration	Yes	No	No	No

As nouns, emigration and out-migration are synonyms defined as:

emigration and out-migration: migration from a place (especially migration from your native country in order to settle in another)

Other synonyms of emigration include expatriation.

emigration (noun)	out-migration (noun)
migration from a place (especially migration from your native country in order to settle in another)	migration from a place (especially migration from your native country in order to settle in another)