unathletic

The story

1. Proto-Indo-European*né
2. Proto-Indo-European*n̥-
3. Proto-Germanic*un-
4. Proto-West Germanic*un-
5. Old Englishun-
6. Middle Englishun-
7. Englishun-
8. Proto-Indo-European*h₂weh₁-
9. Ancient Greekἆθλον (âthlon)
10. Ancient Greekᾱ̓θλέω (āthléō)
11. Ancient Greekἀθλητής (athlētḗs)
12. Ancient Greekᾱ̓θλητῐκός (āthlētĭkós)
13. Latināthlēticu
14. Middle Frenchathletique
15. Englishathletic
16. English todayunathletic

From un- + athletic.