Slavonic vs Slavic language

Slavonic and Slavic language both are nouns.

Word	Noun	Adjective	Verb	Adverb
Slavonic	Yes	Yes	No	No
Slavic language	Yes	No	No	No

As nouns, Slavonic and Slavic language are synonyms defined as:

Slavonic and Slavic language: a branch of the Indo-European family of languages

Other synonyms of Slavonic include Slavic, Slavonic language.

Slavonic (noun)	Slavic language (noun)
a branch of the Indo-European family of languages	a branch of the Indo-European family of languages

Slavonic (adjective)	Slavic language (adjective)
of or relating to Slavic languages