fantasise

The story

1. Proto-Indo-European*bʰeh₂-
2. Proto-Indo-European*bʰh₂nyéti
3. Proto-Hellenic*pʰáňňō
4. Ancient Greekφαίνω (phaínō)
5. Ancient Greekφαντάζω (phantázō)
6. Ancient Greekφᾰ́ντᾰσῐς (phắntăsĭs)
7. Ancient Greekφαντασία (phantasía)
8. Latinphantasia
9. Old Frenchfantasie
10. Middle Englishfantasie
11. Englishfantasy
12. English todayfantasise

From fantasy + -ise.