Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
neutrālis, e, adj. [neuter], in gram., of the gender of substantives, neuter: positio, Quint. 1, 4, 24: nomina, id. 1, 5, 54 et saep.
Hence, adv.: neutrālĭter, as a neuter; Gellius fora navium neutraliter dixit, Charis. p. 55 P.