nonaltruist

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*h₂el-
15. Proto-Indo-European*h₂élyos
16. Proto-Italic*aljos
17. Proto-Italic*aliteros
18. Latinalterī
19. Vulgar Latin*alterui
20. Old Frenchautrui
21. Frenchautrui
22. Frenchaltruisme
23. Englishaltruism
24. Englishaltruist
25. English todaynonaltruist

From non- + altruist.