sleepiness

Etymology tree
Proto-Germanic *slēpaz
Proto-West Germanic *slāp
Proto-Indo-European *-kos
Proto-Germanic *-gaz
Proto-West Germanic *-g
Proto-West Germanic *slāpag
Old English *slǣpiġ
Middle English slepy
English sleepy
Proto-Germanic *-inōną
Proto-Indo-European *-dyé-
Proto-Germanic *-atjaną
Proto-Indo-European *-tus
Proto-Germanic *-þuz
Proto-Germanic *-assuz
Proto-Germanic *-inassuz
Proto-West Germanic *-nassī
Old English -nes
Middle English -nesse
English -ness
English sleepiness
From sleepy + -ness.