nonbeliever

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*h₁ep-
15. Proto-Indo-European*h₁éps
16. Proto-Indo-European*h₁épi
17. Proto-Indo-European*h₁pi
18. Proto-Germanic*bi
19. Proto-Germanic*bi-
20. Proto-West Germanic*bi-
21. Proto-Indo-European*lewbʰ-
22. Proto-Germanic*laubō
23. Proto-Germanic*laubijaną
24. Proto-West Germanic*laubijan
25. Proto-West Germanic*bilaubijan
26. Old Englishbelīefan
27. Middle Englishbileven
28. Englishbelieve
29. Englishbeliever
30. English todaynonbeliever

From non- + believer.