Mordvin vs Mordva

Mordvin and Mordva both are nouns.

Word	Noun	Adjective	Verb	Adverb
Mordvin	Yes	No	No	No
Mordva	Yes	No	No	No

As nouns, Mordvin and Mordva are synonyms defined as:

Other synonyms of Mordvin include Mordva language, Mordvin language, Mordvinian, Mordvinian language.

As nouns, Mordvin and Mordva are synonyms defined as:

Mordvin and Mordva: a member of the agricultural people living in the central Volga provinces of European Russia

Other synonyms of Mordvin include Mordvinian.

Mordvin (noun)	Mordva (noun)
the Finnic language spoken by the Mordvinians	the Finnic language spoken by the Mordvinians
a member of the agricultural people living in the central Volga provinces of European Russia	a member of the agricultural people living in the central Volga provinces of European Russia