adeptness

Etymology tree
Proto-Indo-European *h₂éd
Proto-Italic *ad
Proto-Italic *ad-
Latin ad-
Latin apiō
Proto-Indo-European *-sḱéti
Proto-Italic *-skō
Latin -scō
Latin apīscor
Latin adipīscor
Latin adeptusbor.
French adeptebor.
English adept
Proto-Germanic *-in-
Proto-Indo-European *-h₂
Proto-Indo-European *-éh₂
Proto-Indo-European *-yéti
Proto-Indo-European *-eh₂yéti
Proto-Indo-European *-h₂ti
Proto-Germanic *-ōną
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 adeptness
From adept + -ness.