Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
mŭrĭātĭcus, a, um, adj. [muria], pickled or lying in brine; perh. only as subst.: mŭrĭātĭcum, i, n., a pickled fish (Plautinian), Plaut. Poen. 1, 2, 32: (coqua) scit, muriatica ut maceret, id. ib. 1, 2, 38.