A top man, or prince, among the canting crew: also the chief rogue of the gang, or the completest cheat. CANT.
Pretty. A dimber cove; a pretty fellow. Dimber mort; a pretty wench. CANT. ...
Dictionary of The Vulgar Tongue by Francis Grose
A rascal. See dimber. ...
An old word for lubberly rogue. ...
The Sailor's Word-Book
The chief of a gang of thieves or gypsies. ...