From Wiktionary, the free dictionary
Variant of weren't.
worn't
- (largely obsolete, still found in some dialects, particularly in UK) Alternative spelling of weren't
c. 1872, John Hartley, Yorkshire Ditties, Second Series[1]:It worn't long befoor he coom // To see ha matters stood;
1892 April 9, Punch, or the London Charivari[2], volume 102:Which on 'em was Oxford? The inside one. No, it worn't—they was outside.
1904, Folk Tales Every Child Should Know[3]:There worn't nothin' in it but a spinnin' wheel and a stool.