objective case vs accusative

objective case and accusative both are nouns.

Word	Noun	Adjective	Verb	Adverb
objective case	Yes	No	No	No
accusative	Yes	Yes	No	No

As nouns, objective case and accusative are synonyms defined as:

objective case and accusative: the case of nouns serving as the direct object of a verb

Other synonyms of objective case include accusative case.

objective case (noun)	accusative (noun)
the case of nouns serving as the direct object of a verb	the case of nouns serving as the direct object of a verb

objective case (adjective)	accusative (adjective)
	serving as or indicating the object of a verb or of certain prepositions and used for certain other purposes
	containing or expressing accusation