Haggai Syllabification: (Hag·gai)Pronunciation: /ˈhagēˌī, ˈhagī/Definition of Haggai a Hebrew minor prophet of the 6th century bc. a book of the Bible containing Haggai’s prophecies of a glorious future in the Messianic age. Haggai in other Oxford dictionaries Definition of Haggai in the British & World English dictionary