Russian vs Slavonic

Russian and Slavonic both are nouns.

Word	Noun	Adjective	Verb	Adverb
Russian	Yes	Yes	No	No
Slavonic	Yes	Yes	No	No

As nouns, Slavonic is a hypernym of Russian; that is, Slavonic is a word with a broader meaning than Russian:

Other hypernyms of Russian include Slavic, Slavic language, Slavonic language.

Russian (noun)	Slavonic (noun)
the Slavic language that is the official language of Russia	a branch of the Indo-European family of languages
a native or inhabitant of Russia

Russian (adjective)	Slavonic (adjective)
of or pertaining to or characteristic of Russia or its people or culture or language	of or relating to Slavic languages