Historically "Warlock" has been used to to describe a male practitioner of Magical Arts. It also has been used as a synonym for a male witch and remains popular with the mass media. Although it is certainly not commonly used within the modern witchcraft community.
Warlock is a controversial word and the usage enrages many practitioners of magic. It has also been used to indicate that the person using this title is an outsider to the magical community, unaware of magical nuances and etiquette. There is much debate as to it's origins.
One speculation is that it evolved from the Norse word "Vardlokkur," which means a wise man who guards or (locks) the gates of knowledge. He binds evil spirits to prevent them from entering through the portals, thus creating wards.
This Warlock is a "Spiritual Warrior" and a practitioner of protective magic, especially the use of protective runes. If Warlock derives from "Vardlokkur" then it is derived from pagan sources and refers to genuine pagan tradition.
Vardlokkur names not only the practitioner, but it may also name the magical tradition of using runes to bind, harm and provide protection.
"Warlock" might be derived not only from the above mentioned source, but also from the Old English word "Waeroga", literally translated as "oath breaker". But also historically used to indicate "devil."
The word "Warlock" may come from both roots and may reflect the British Christian perceptions of the Pagan Norse invaders, "The North men" or Vikings. Regardless of it's origin, the Anglo-Saxon term comes from a squarely Christian tradition. It is the Christian word used to describe those who the Christians held in contempt.
The "Witch Hunters" applied it to their prey. The sting of this word still remains in most witchcraft communities. The exception would be those practitioners drawing heavily or exclusively from the Norse Shamanic traditions, who may even favor the name.
Good Luck, Good Love and Good Magic,