köken: Inherited from Proto-Slavic *lěnostь, based on *lěnъ (“lazy”); compare Old East Slavic лѣнꙑи (lěnyi), Belarusian ляны́ (ljaný), Bulgarian лен (len), Serbo-Croatian ли̏jен, Czech líný, etc. By surface analysis, *лено́й (*lenój, “lazy”) + -ость (-ostʹ), based on a no-longer existing adjectival form of лень (lenʹ, “laziness”), replaced in modern Russian with лени́вый (lenívyj) (but dialectal лено́й…