enslave

The story

1. Proto-Indo-European*h₁én
2. Proto-Italic*en
3. Proto-Italic*en-
4. Latinin-
5. Old Frenchen-
6. Middle Englishen-
7. Englishen-
8. Proto-Indo-European*ḱlewH-der.?
9. Proto-Slavic*slov-
10. Proto-Slavic*Slov-?
11. Proto-Slavic*slověninъ
12. Ancient GreekΣκλαβηνός (Sklabēnós)
13. Medieval GreekΣκλᾰ́βος (Sklắbos)
14. Late LatinSclavus
15. Medieval Latinsclavus
16. Old Frenchesclave
17. Middle Englishsclave
18. Englishslave
19. English todayenslave

From en- + slave.