nonpermanent

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*per-
15. Proto-Italic*peri-
16. Latinper-
17. Proto-Indo-European*men-
18. Proto-Indo-European*m̥néh₁yeti
19. Proto-Italic*m(V)nēō
20. Latinmaneō
21. Latinpermaneō
22. Middle Frenchpermanent
23. Englishpermanent
24. English todaynonpermanent

From non- + permanent.