Advent vs Parousia

Advent and Parousia both are nouns.

Word	Noun	Adjective	Verb	Adverb
Advent	Yes	No	No	No
Parousia	Yes	No	No	No

As nouns, Advent and Parousia are synonyms defined as:

Advent and Parousia: (Christian theology) the reappearance of Jesus as judge for the Last Judgment

Other synonyms of Advent include Second Advent, Second Coming, Second Coming of Christ.

Advent (noun)	Parousia (noun)
(Christian theology) the reappearance of Jesus as judge for the Last Judgment	(Christian theology) the reappearance of Jesus as judge for the Last Judgment
the season including the four Sundays preceding Christmas