vocative vs linguistics

vocative and linguistics both are nouns.

Word	Noun	Adjective	Verb	Adverb
vocative	Yes	Yes	No	No
linguistics	Yes	No	No	No

vocative (noun)	linguistics (noun)
the case (in some inflected languages) used when the referent of the noun is being addressed	the scientific study of language
	the humanistic study of language and literature

vocative (adjective)	linguistics (adjective)
relating to a case used in some languages