Dark Magic is the term used for certain schools and styles of magic which the populace of Aravorn by and large consider feel shouldn't be used. Note this doesn't hold true for all forms of magic. Teleportation is considered a form of Demon Magic, but the people of Dingirra make use of this discipline in the form of magic portals.
 Forms of Dark Magic
The magic of witches. While most of the details are currently unknown, most people believe witches serve a dark master and reject their presence.
The magic of death. While a necromancer isn't necessarily evil, society definitely has little patience for those traffic in such areas. Noone likes to see granny raising from the grave and walking around halfrotten, even if no harm to living people is done.
A catch-all category for those with demon magic. Demon magic has a detrimental effect on plant life, even killing it outright. Even if the magic isn't used for killing, it's very presence causes a chaotic effect. This includes peoples like the Dark Elves born tainted with Demon Blood.
Some practitioners of Dark Magic have revealed they can read someone else's mind (such as telling when someone is telling a lie.) Some accomplish this by reading auras.
Magic capable of moving great distances, bypassing the surrounding geography.
The magic of transforming one's own shape.