Used as a mild oath.
[Alteration of by God.]
an emphatic exclamation, regarded as a characteristic utterance of Irish people
[C19: euphemistic alteration of by God!]
be•gor•ra(bɪˈgɔr ə, -ˈgɒr ə, bi-)
interj. Irish Eng.
(used as a euphemism for by God): It's a fine day, begorra.