From Ògún (the òrìṣà of iron, war and metalwork) + bí ("give birth") + yìí ("this one"): "Ògún gave birth to this child." A family name marking a lineage that served Ògún.
Source: Yoruba òrìṣà-lineage surname, cross-referenced across Wiktionary (Ògúnbíyìí), the DiscoverYorùbá surnames guide, and wisdomlib