The story
- Proto-Indo-European*h₁én
- Proto-Italic*en
- Proto-Italic*en-
- Latinin-
- Latintendō
- Latinintendō
- Medieval Latinintentiō
- Proto-Indo-European*h₂el-
- Proto-Indo-European*h₂élisder.?
- Medieval Latinintentiōnālis
- English todayintentional
Borrowed from Medieval Latin intentiōnālis, from intentiō + -ālis. By surface analysis, intention + -al.
Etymology from Wiktionary, CC BY-SA 4.0.