Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
stercŏrōsus, a, um, adj. [stercus], full of excrements or dung, well manured: aqua, full of filth, impure, Col. 8, 3, 8; cf. Sen. Q. N. 3, 26, 6: solum, Col. 11, 3, 43: herbae, id. 9, 4, 7.
Sup.: locus, Cato, R. R. 46.