Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
dē-tŭmesco, mŭi, 3, v. inch. n., to cease swelling, to settle down, subside (postAug. and very rare): stagna lacusque sonori detumuere, Stat. Th. 3, 259: animi maris, id. ib. 5, 468.
Trop.: odia, Petr. 109, 5: colla superbarum gentium, Amm. 15, 8, 7.