Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
in-dĕcŏro, āre, v. a., to disgrace, disfigure (rare): me sermone indecorans, Att. ap. Non. 125, 1 (Fragm. Trag. v. 459 Rib.): indecorant bene nata culpae, Hor. C. 4, 4, 36 (al. dedecorant).