Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
ăcĭpenser, ĕris, and ăcĭpensis, is (also aquip., not accipenser), m., = ἀκκῐπησίος, a fish very highly esteemed in the age of the greatest luxury of the Romans, perh. the sturgeon, Cic. Tusc. 3, 18; id. Fin. 2, 8; Hor. S. 2, 2, 47; Ov. Hal. 132.