semimystical

The story

1. Proto-Indo-European*sem-
2. Proto-Indo-European*sēmi
3. Latinsēmi-
4. Englishsemi-
5. Proto-Indo-European*mewH-
6. Proto-Indo-European*mewH-ye-
7. Ancient Greekμῡ́ω (mū́ō)
8. Ancient Greekμῠέω (mŭéō)
9. Ancient Greekμῠ́στης (mŭ́stēs)
10. Ancient Greekμῠστῐκός (mŭstĭkós)
11. Latinmysticus
12. Old Frenchmistique
13. Englishmystic
14. Proto-Indo-European*h₂el-
15. Proto-Indo-European*h₂élisder.?
16. Englishmystical
17. English todaysemimystical

From semi- + mystical.