E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
To cast a leglin-girth. To have a screw loose; to have made a faux pas; to have ones reputation blown upon. A leglin-girth is the lowest hoop of a leglin or milk-pail. (See Sir Walter Scott: Fortunes of Nigel, chap. xxii.)