Ireland vs Eire

Ireland and Eire both are nouns.

Word	Noun	Adjective	Verb	Adverb
Ireland	Yes	No	No	No
Eire	Yes	No	No	No

As nouns, Ireland and Eire are synonyms defined as:

Ireland and Eire: a republic consisting of 26 of 32 counties comprising the island of Ireland; achieved independence from the United Kingdom in 1921

Other synonyms of Ireland include Irish Republic, Republic of Ireland.

Ireland (noun)	Eire (noun)
an island comprising the republic of Ireland and Northern Ireland	a republic consisting of 26 of 32 counties comprising the island of Ireland; achieved independence from the United Kingdom in 1921
a republic consisting of 26 of 32 counties comprising the island of Ireland; achieved independence from the United Kingdom in 1921