Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
accūsātīvus, a, um [id., prop. belonging to an accusation, hence], in gramm. with or without casus, the accusative case, as if the defendant in a suit, Varr. L. L. 8, § 67 Müll. (in the prec. §: casus accusandi); Quint. 7, 9, 10, and all the later writers.
Hence, praepositiones accusativae, i. e. those joined with the accusative, Serv. ad Verg. A. 1, 28 al.