This etymology is missing or incomplete. Please add to it, or discuss it at the Etymology scriptorium. Particularly: “Maybe Bantu origin. Compare Chichewa Mulungu. Is this BLR 1220? Taylor (1891) claims that old Swahili had ungu for heaven, which would have been lungu. From this Mulungu "Possessor of the vault (of heaven)" was created; Mulungu became Muungu and later Mungu”
Frankl, P. J. L. (1990) “The Word for "God" in Swahili”, in Journal of Religion in Africa[1], volume 20, number 3, →DOI, pages 269-275
Frankl, P. J. L. (1995) “The Word for 'God' in Swahili: Further Considerations”, in Journal of Religion in Africa[2], volume 25, number 2, →DOI, pages 202-211