Warlock, according to a Google search...
"It was used to denote a traitor to the Craft..."
"Derogatory term for a Male Witch."
"An old-English term for oath breaker."
"A derogatory term which literally means "oathbreaker". It is a common misconception that male witches are called warlocks. However, male witches are no different than females in this respect and so they are simply called witches."
"Very old and derogatory term (Old Middle English) misguidedly referring to a male witch. It means oath-breaker, traitor or liar...."