The story
- Proto-Indo-European*ten-
- Proto-Indo-European*tend-
- Proto-Indo-European*téndeti
- Proto-Italic*tendō
- Latintendō
- Latintendēns
- Medieval Latintendentia
- Englishtendency
- Proto-Indo-European*h₃ed-
- Proto-Indo-European*h₃édosder.?
- English todaytendentious
From tendency + -ious, after German tendenziös.
Etymology from Wiktionary, CC BY-SA 4.0.