A derogatory term for an idiot. A modern translation would be, "Faggot of an old English court house". Made popular by the short comedy film, "The Duel at Blood Creek".
"This libelous gagger sullied my good name in the Times!"
"I only called you the "Ponce of the Old Bailey." I thought it rather amusing."
"It was not, sir. It was an insult, sir."