Green’s Dictionary of Slang

(Ulster) severe, harsh, esp. of a beating; thus sevendably adv.

1864, 1867, 1870		Hotten Sl. Dict. 224: sevendible a very curious word, used only in the North of Ireland, to denote something particularly severe, strong, or sound. It is, no doubt, derived from seven-double ? that is, seven-fold ? and is applied to linen cloth, a beating, a reprimand, &c.
1864		Armagh Guardian 23 Dec. 5/6: He gave him a sevendible fine beating.
1880		Northern Whig 7 Aug. 6/1: ‘evendible’ (severe).
1901		Northern Whig 9 Apr. 6/3: ‘Sevendible’ is a word that carries with it suggestions of weather [...] of the wintriest description.
1911		F.E. Crichton Soundless Tide 188: The damage to property was sevendible.
1929		Ballymena Obs. 20 Dec. 11/7: ‘Bad,’ says he, ‘sevendible bad, never was worse’.
1956		Ballymena Obs. 24 Feb. 10/4: ‘Did you not hear a wild dunnerin’, sir? [...] It was a sevendible clatter altogether’.
1979		P. Tunney Stone Fiddle n.p.: The two O’Connors fell upon their Protestant friends and trounced them sevendably [BS].