Yenisey vs Yenisei

Yenisey and Yenisei both are nouns.

Word	Noun	Adjective	Verb	Adverb
Yenisey	Yes	No	No	No
Yenisei	Yes	No	No	No

As nouns, Yenisey and Yenisei are synonyms defined as:

Yenisey and Yenisei: a Russian river in Siberia; rises in mountains near the Mongolian border and flows generally northward into the Kara Sea

Other synonyms of Yenisey include Yenisei River, Yenisey River.

Yenisey (noun)	Yenisei (noun)
a Russian river in Siberia; rises in mountains near the Mongolian border and flows generally northward into the Kara Sea	the Uralic language spoken by the Yeniseian
	a Russian river in Siberia; rises in mountains near the Mongolian border and flows generally northward into the Kara Sea