Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
lŭtesco, ĕre, v. inch. n. [2. lutum], to turn to mud, become muddy: litora, quae limo caenoque lutescunt, Col. 8, 17, 9: cava terra lutescit, Furius Antias ap. Gell. 18, 11; id. ap. Non. 133, 26.