The story
- Proto-Indo-European*dwóh₁
- Proto-Indo-European*trísinflu.
- Proto-Indo-European*d(w)is-
- Proto-Italic*dis-
- Latindis-
- Latinputus
- Latinputō
- Latindisputo
- Latindisputābili
- Englishdisputable
- Proto-Indo-European*leyg-
- Proto-Germanic*līką
- English todaydisputably
From disputable + -ly, equivalent to dispute + -ably.
Etymology from Wiktionary, CC BY-SA 4.0.