Sh-t Sack (Grose 1811 Dictionary)

A dastardly fellow: also a non-conformist. This appellation is said to have originated from the following story:—After the restoration, the laws against the non-conformists were extremely severe. They sometimes met in very obscure places: and there is a tradition that one of their congregations were assembled in a barn, the rendezvous of beggars and other vagrants, where the preacher, for want of a ladder or tub, was suspended in a sack fixed to the beam. His discourse that day being on the last judgment, he particularly attempted to describe the terrors of the wicked at the sounding of the trumpet, on which a trumpeter to a puppet-show, who had taken refuge in that barn, and lay hid under the straw, sounded a charge. The congregation, struck with the utmost consternation, fled in an instant from the place, leaving their affrighted teacher to shift for himself. The effects of his terror are said to have appeared at the bottom of the sack, and to have occasioned that opprobrious appellation by which the non-conformists were vulgarly distinguished.