ad in ‧ fi ‧ ni ‧ tum /ˌæd ɪnfəˈnaɪtəm/ BrE AmE adverb formal
[ Date: 1600-1700 ; Language: Latin ; Origin: 'to an endless length of time' ]
continuing without ever ending – often used humorously:
I have to explain A, then B, and C, and so on ad infinitum.