Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
dēsŭē-făcĭo, fēci, factum, 3, v. a. [desueo], to disuse, disaccustom, bring out of use (very rare): catuli (a matre) minutatim desuefiunt, Varr. R. R. 2, 9, 12: multitudo desuefacta a contionibus, *Cic. Clu. 40, 110; cf. Tert. Pall. 4.