The story
- Proto-Indo-European*de
- Proto-Indo-European*déh₁
- Proto-Italic*dē
- Latindē
- Latinde-
- Proto-Indo-European*dʰeh₁-
- Proto-Indo-European*dʰeh₁k-
- Proto-Indo-European*dʰh₁kyéti
- Proto-Italic*θakjō
- Proto-Italic*fakjō
- Latinfacio
- Latindēficiō
- Latindēfectus
- Englishdefect
- Englishdefectible
- English todaydefectibility
From defectible + -ity.
Etymology from Wiktionary, CC BY-SA 4.0.