nonredeemable

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. Latinred-
15. Proto-Indo-European*h₁em-
16. Proto-Indo-European*h₁émeti
17. Proto-Italic*emō
18. Latinemō
19. Latinredimō
20. Old Frenchredimer
21. Middle Englishredemen
22. Englishredeem
23. Englishredeemable
24. English todaynonredeemable

From non- + redeemable.