大晦日[oomisoka] New Year's Eve
韜晦[toukai] hidden (talents, etc.)
晦渋[kaijuu] ambiguous
晦冥[kaimei] darkness
大晦[ootsugomori] the last day of the year

晦ます[kuramasu] to abscond
晦む[kuramu] to be dazzled by
自己韜晦[jikotoukai] concealing one's talents, position, status, intentions, etc.
天地晦冥[tenchikaimei] The world is covered in darkness

暗い[kurai] dark
暗がり[kuragari] darkness
暗に[anni] implicitly
暗やみ[kurayami] darkness
暗うつ[anutsu] gloom

暗雲[anun] dark clouds
暗褐色[ankasshoku] dark brown
暗きょ[ankyo] subterranean drain
暗君[ankun] foolish ruler
暗号[angou] code