unenslave

The story

1. Proto-Indo-European*h₂ent-
2. Proto-Indo-European*h₂énts
3. Proto-Germanic*anda-
4. Proto-West Germanic*anda-
5. Old Englishand-
6. Old Englishon-
7. Middle Englishon-
8. Englishun-
9. Proto-Indo-European*h₁én
10. Proto-Italic*en
11. Proto-Italic*en-
12. Latinin-
13. Old Frenchen-
14. Middle Englishen-
15. Englishen-
16. Proto-Indo-European*ḱlewH-der.?
17. Proto-Slavic*slov-
18. Proto-Slavic*Slov-?
19. Proto-Slavic*slověninъ
20. Ancient GreekΣκλαβηνός (Sklabēnós)
21. Medieval GreekΣκλᾰ́βος (Sklắbos)
22. Late LatinSclavus
23. Medieval Latinsclavus
24. Old Frenchesclave
25. Middle Englishsclave
26. Englishslave
27. Englishenslave
28. English todayunenslave

From un- (prefix meaning 'de-') + enslave.