Green’s Dictionary of Slang

kerwhallop v.

also cowhallop, cowollap, kawhallop, kerwallop, kerwhollop, kerwollop, kerwollup, keswollup
[ker- pfx + SE wallop]

to hit hard and suddenly, to smack.

[US] ‘M’Cracken’s Experience’ in T.A. Burke Polly Peablossom’s Wedding 60: The pop-eyed feller looked as ef he thought he was about to ketch the orfullest cowhallopin he’d ever seed. [Ibid.] ‘The Amateur Ticket-Vender’ 107: He would get the most allfired cowollaping he ever hearn talk of!
[US]W. Sketch & ‘Nelse’ The Down-Trodden 64/2: You can kerwallop me if you don’ have one of the worst flamby gusters that ’as come keslap agin’ the old ’ganies.
[US]‘Artemus Ward’ Artemus Ward, His Book 70: I darsunt tell her of the fires which was rajin in my manly Buzzum. I’d try to do it but my tung would kerwollup up agin the roof of my mowth & stick thar.
[US]Belmont Chron. (St Clairsville, OH) 5 Jan. 3/4: Be jabers, me boys, have you heard from the raid [...] How Sherman kerwhollopped the Rebel Hardee?
[US]Schele De Vere Americanisms 590: Keswollup and kewhollux, known in England, are rare in America.
[US]E.S. Ellis Huge Hunter in Beadles Half Dime Library XI:271 5/1: I kerwholloped in the water.
[US]Shenandoah Herald (Woodstock, VA) 21 June 4/6: ‘No, Jonas. You tackled that b’ar agin my advice.’ ‘And kerwholloped him?’.
[UK]Farmer & Henley Sl. and Its Analogues IV 93/2: Keswollup.
[UK]J. Ware Passing Eng. of the Victorian Era 162/1: Kerwollop (Amer., 19 cent.). To beat, or wallop.