Lewis & Short

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.