Definition of "garreter"

Not that the existence of Grub street is to be doubted: it was, indeed, a grim actuality, and many a garreter realised by experienceHow unhappy's the fateTo live by one's pateAnd to be forced to write hackney for bread.

1972, Pat Rogers, Grub Street: Studies in a Subculture, page 384

[A]bout 40 were burglars, "dancers," "garreters," and other adepts with the skeleton keys.

1889, Charles Tempest Clarkson, J. Hall Richardson, Police!, page 260