decorum(appropriate social behavior; propriety) noun [UK: dɪˈk.ɔː.rəm] [US: dɪˈk.ɔː.rəm]
indecoroso adjective
unseemly(inconsistent with standards, etc.) adjective [UK: ʌn.ˈsiːm.li] [US: ʌn.ˈsiːm.li]Asking for seconds would be unseemly. = Chiedere il bis sarebbe indecoroso.