postconceptionally

The story

1. Proto-Indo-European*pós
2. Proto-Indo-European*pósti
3. Proto-Italic*posti
4. Old Latinposte
5. Latinpost
6. Englishpost-
7. Proto-Indo-European*ḱe?
8. Proto-Indo-European*ḱóm
9. Proto-Italic*kom
10. Proto-Italic*kom-
11. Latincon-
12. Proto-Indo-European*kap-
13. Proto-Indo-European*kapyéti
14. Proto-Italic*kapjō
15. Latincapiō
16. Ancient Greekσῠλλᾰμβᾰ́νω (sŭllămbắnō)
17. Latinconcipiō
18. Latinconceptiō
19. Old Frenchconception
20. Middle Englishconcepcioun
21. Englishconception
22. Proto-Indo-European*h₂el-
23. Proto-Indo-European*h₂élisder.?
24. Englishconceptional
25. Englishpostconceptional
26. Proto-Indo-European*leyg-
27. Proto-Germanic*līką
28. English todaypostconceptionally

From postconceptional + -ly.