subs. phr. (old).An eighteenth century wig: the back hair was enclosed in an ornamental bag: hence BAG-WIGGED = wearing a BAG-WIG.
1760. FOOTE, The Minor [T. L. KINGTON-OLIPHANT, The New English, ii. 179. There are the new substantives], BAG WIG.
1766. C. ANSTEY, The New Bath Guide, Letter x., 60. BAG-WIG, and lacd ruffles, and black solitaire?
1775. SHERIDAN, St. Patricks Day, ii. 4. (1883), 236. Pig-tailed lawyers and BAG-WIGGED attorneys.
1850. IRVING, Oliver Goldsmith, xxv. 252. Walking the Strand in grand array with BAG-WIG and sword.
1866. W. D. HOWELLS, Venetian Life, xxi. Expect at every turn to come upon intriguing spectres in BAG-WIGS, immense hoops and patches.