Belorussia vs Republic of Belarus

Belorussia and Republic of Belarus both are nouns.

Word	Noun	Adjective	Verb	Adverb
Belorussia	Yes	No	No	No
Republic of Belarus	Yes	No	No	No

As nouns, Belorussia and Republic of Belarus are synonyms defined as:

Belorussia and Republic of Belarus: a landlocked republic in eastern Europe; formerly a European soviet

Other synonyms of Belorussia include Belarus, Byelarus, Byelorussia, White Russia.

Belorussia (noun)	Republic of Belarus (noun)
a landlocked republic in eastern Europe; formerly a European soviet	a landlocked republic in eastern Europe; formerly a European soviet