Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
dē-dĕcŏro, āvi, ātum, 1, v. a., to disgrace, dishonor, bring to shame (class.): mores, quibus boni se dedecorant, Plaut. Trin. 2, 2, 23: me flagitiis suis, id. Bacch. 3, 3, 95; cf.: se flagitiis, Sall. J. 85, 42; * Suet. Ner. 36; Ter. Hec. 2, 1, 13: et urbis auctoritatem et magistri, Cic. Off. 3, 2, 6; Prop. 3 (4), 22, 36; Hor. Od. 4, 4, 36 (where others read indecorant).