Etimology of Warlock

A warlock is a male practitioner of witchcraft. 

The most commonly accepted etymology derives "warlock" from the Old English wǣrloga, which meant "breaker of oaths" or "deceiver" and was given special application to the devil around 1000. The word was used in early modern Scots as the male equivalent of "witch" (which can be male or female, but has historically been used predominantly for females. The meaning "one in league with the devil" is recorded from c. 1300.  The ending in "-ck" (1680s) and meaning "male equivalent of a witch" (1560s) are from. In Scotland, the term "warlock" may have become associated with male witches due to the idea that they had made pacts with the devil and thus had betrayed the Christian faith and broke their baptismal vows or oaths.

 The word "warlock" passed into Romantic literature and ultimately 20th-century popular culture, and in modern usage, a warlock is often seen as the dark embodiment of magic, while a wizard is seen as good and kind enough to give out advice. Warlocks, on the other hand, are good at deceiving people.