autoresponse

The story

1. Proto-Indo-European*h₂ew
2. Proto-Indo-European*tó-
3. Proto-Hellenic*autós
4. Proto-Indo-European*h₂ew
5. Ancient Greekαὖ (aû)
6. Ancient Greekτόν (tón)
7. Ancient Greekαὐτός (autós)
8. Ancient Greekαὐτο- (auto-)
9. Proto-Indo-European*men-
10. Proto-Indo-European*mn̥tós
11. Proto-Hellenic*mətós
12. Ancient Greekαὐτόμᾰτος (autómătos)
13. Ancient Greekαὐτόμᾰτον (autómăton)
14. Classical Latinautomatum
15. New Latinautomaticus
16. Englishautomaticclip.
17. Englishauto-
18. Proto-Italic*wre-
19. Latinre-
20. Proto-Indo-European*spend-
21. Proto-Indo-European*spondéyeti
22. Proto-Italic*spondejō
23. Proto-Italic*spondeō
24. Latinspondeō
25. Latinrespondeō
26. Latinrespōnsum
27. Old Frenchrespuns
28. Middle Englishrespounse
29. Englishresponse
30. English todayautoresponse

From auto- + response.