underproductivity

The story

1. Proto-Indo-European*h₁én
2. Proto-Indo-European*h₁entér
3. Proto-Indo-European*h₂én
4. Proto-Indo-European*dʰeh₁-?
5. Proto-Indo-European*(H)n̥dʰí
6. Proto-Indo-European*(H)n̥dʰér
7. Proto-Germanic*under
8. Proto-West Germanic*undar
9. Old Englishunder-
10. Middle Englishunder-
11. Englishunder-
12. Proto-Indo-European*per-der.?
13. Proto-Indo-European*pér
14. Proto-Indo-European*pró
15. Proto-Indo-European*pro-
16. Proto-Italic*pro-
17. Latinprō-
18. Proto-Indo-European*dewk-
19. Proto-Indo-European*déwkti
20. Proto-Italic*doukō
21. Latindūcō
22. Latinprōdūcō
23. Late Latinprōductīvus
24. Englishproductive
25. Englishproductivity
26. English todayunderproductivity

From under- + productivity.