nonthyroid

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*dʰwer-
15. Proto-Hellenic*tʰurā
16. Ancient Greekθῠ́ρᾱ (thŭ́rā)
17. Ancient Greekθῠρεός (thŭreós)
18. Proto-Indo-European*weyd-
19. Proto-Indo-European*wéydos
20. Proto-Hellenic*wéidos
21. Ancient Greekεἶδος (eîdos)
22. Ancient Greekθῠρεοειδής (thŭreoeidḗs)
23. New Latinthyreoīdēs
24. Englishthyroid
25. English todaynonthyroid

From non- + thyroid.