VAIN-Glorious,
or Ostentatious Man, one that boasts without Reason, or, as the Canters say, pisses more than he drinks.
· 
· 
Entry taken from 1736 Canting Dictionary, by Nathan Bailey.
Vain-glorious in the 1811 Vulgar Tongue
Also see examples in Canting Songs and Slang Rhymes collected by John S. Farmer (1896).