emotionless

The story

1. Proto-Indo-European*h₁éǵʰ
2. Proto-Indo-European*h₁éǵʰs
3. Proto-Italic*eks
4. Latinex
5. Latinex-
6. Proto-Indo-European*m(y)ewh₁-
7. Proto-Indo-European*m(y)owh₁éyeti
8. Proto-Italic*moweō
9. Latinmoveō
10. Latinēmoveō
11. Vulgar Latin*exmovēre
12. Old Frenchesmovoir
13. Middle Frenchesmouvoir
14. Middle Frenchemotion
15. Englishemotion
16. Proto-Indo-European*lewh₁-
17. Proto-Indo-European*lewHs-
18. Proto-Germanic*leusaną
19. Proto-Germanic*lausaz
20. English todayemotionless

From emotion + -less.