Definition of "gurt"

Zo ′e bought a slap-up rod and tackle, and, ev coose, a darn gurt book vull o′ vlies — talk′d about ketchin′ whackin′ trout, and me — ap a salmon the fust time.

1842, The Sportsman, Volume VI: January to June, page 103

“That was the word,” said Farmer Forder. “Hav′n pocketed the tuppunce, the chap as show′d off the clock opened the case, and let me zee the works of ′un, and wonderful works they was : wheels within wheels, and all sorts o′ crinkum-crankums, like a gurt puzzle. […] ”

1845, Douglas Jerrold, editor, Shilling Magazine, Volume II: July to December, page 416

“Well, Tom, where did those birds settle?”“Down there, sir, under that gurt oak-tree.”Not a bird, however, was to be found.

1884, John Coker Egerton, Sussex Folk and Sussex Ways: Stray Studies in the Wealden Formation of Human Nature‎, page 27