Green’s Dictionary of Slang

(Irish/Scot.) a belch; also as v.

1966		P. Boyle At Night All Cats Are Grey 73: Mostly he just chooked. That is until he started to rift. Chook! Chook! Rift!
1995		A. Higgins Donkey’s Years 49: The Bowsy just let out a rift [...] Mumu called belching a rift; rifting was rude.
2005		(con. 1960s) A. Bennett Untold Stories (2006) 41: ‘Well,’ said Mam resignedly, ‘it doesn’t do for us. Our Kathleen used to put it in the trifle and it always rifted up on me.’.