From Wiktionary, the free dictionary
hebu
- hey (said to get attention)
- Almasi, Oswald, Fallon, Michael David, Nazish, Pardhan Wared (2014) Swahili Grammar for Introductory and Intermediate Levels, Lanham • New York • Oxford: University Press of America, →ISBN, page 372: “Ebu! or Hebu! – Usually expresses surprise or even disapproval.”