You can complete the translation of Guni given by the German-English Collins dictionary with other dictionaries: Wikipedia, Lexilogos, Langenscheidt, Duden, Wissen, Oxford, Collins dictionaries.
Ahi son of Abdiel, son of Guni, was head of their ancestral houses.
Ahi the son of Abdiel, the son of Guni, chief of their fathers' houses.