nonargumentative

The story

1. Proto-Indo-European*né
2. Proto-Germanic*ne
3. Proto-Indo-European*ís?
4. Proto-Indo-European*h₁óynos
5. Proto-Germanic*ainaz
6. Proto-Germanic*nainaz
7. Proto-West Germanic*nain
8. Old Englishnān
9. Middle Englishnon
10. Old Englishnān
11. Old Englishnān-
12. Middle Englishnon-
13. Englishnon-
14. Proto-Indo-European*h₂erǵ-
15. Proto-Indo-European*h₂érǵus
16. Proto-Italic*argusder.?
17. Latinarguō
18. Latinargūmentum
19. Latinargūmentor
20. Medieval Latinargūmentātīvus
21. Middle Englishargumentatif
22. Englishargumentative
23. English todaynonargumentative

From non- + argumentative.