Sorcery
See Category:Sorcery Spells for a list of Sorcery spells.'
Sorcery as a category, is broadly defined as the manipulation of mana that exists outside the magician's attuned realm.
There are two somewhat arbitrary subtypes, often described as "sorcery" (lower case s) or "sorcerous casting" and "Sorcery" (capital s) or "True Sorcery."
Sorcerous Casting
Sorcerous casting is when a magic user attempts to cast a spell designed to use another type of mana. This may be as simple as a Cleric trying casting Clear Vision, but it comes with the danger of sorcerous backlash. The danger of this is that even when not attempting to do so, any attempt by a magic user to manipulate mana will either wholly or partially include their native mana as an unavoidable reflexive action. Without even intending to, the Cleric would end up funneling at least a small amount of holy mana into the Clear Vision spell, which it is not designed to handle, and occasionally result in catastrophic consequences.
While sorcerous casting is not in and itself illegal in most locals due to the general inability to separate it from normal spellcasting, the body-destroying backlashes have caught the attention of provincial authorities, and may soon come with legal troubles.
True Sorcery
Sorcery (capital S) or "true sorcery" is the act of using spells specifically designed and requiring two or more mana types to function. At a fundamental level, different mana types are incompatable, and when forced to act together result in spells that are invariably destructive in nature. Sorcery is characterized by violence -- while the means of sorcery are varied, inevitably there is something being undermined or destroyed. This can be as blatant as Blackfire consuming a man utterly, or as pervasive as Teleology gnawing at the underpinnings of possibility and reality.
Regardless of whether or not an onlooker understands what is happening, true sorcery evokes a feeling of terrible wrongness, which will result in a reaction by the local law, if present.