The story
- Proto-Indo-European*h₁én
- Proto-Indo-European*h₁n̥tér
- Proto-Italic*n̥ter
- Latininter
- Latininter-
- Proto-Indo-European*leǵ-
- Proto-Indo-European*léǵeti
- Proto-Italic*legō
- Latinlegō?
- Proto-Indo-European*h₂leg-
- Proto-Indo-European*h₂légeti
- Proto-Italic*legō?
- Latinintelligō
- Latinintelligēns
- Middle Frenchintelligent
- Englishintelligent
- Proto-Indo-European*leyg-
- Proto-Germanic*līką
- English todayintelligently
From intelligent + -ly.
Etymology from Wiktionary, CC BY-SA 4.0.