Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
† ēthĭcus, a, um, (scanned ĕthĭcīs, Prud. Hamart. 583), adj., = ἠθικός, moral, ethic (post-class.): res, ethics, Gell. 1, 2, 4: dictio, which shows the character, Sid. Ep. 8, 11.
Hence adv.: ēthĭcos = ἠθικῶς, morally: dicere, Sen. Contr. 2, 12, 8.