The Act of Assassination is formalized, much like dueling was. Should an assassin kill someone without proper notification or letters of recognition they are considered a criminal and a murderer and will be hunted down and killed without mercy or question. Pulling off a proper assassination demonstrates skill and elan (collateral damage, civilian casualties, etc are not tolerated) and earns the Assassin accolades and recognition. It becomes a high art.
Mordforsog, the Danish word for attempted murder
Snigmord, the Danish word for Assassination.
Snigmordforsog, the declaration of intent to commit assassination
Should a person have Snigmordforsog called upon them, they are free to attempt to counter-assassinate the person who is going to have them killed. This ranges from actions and traps to kill the assassin. (Forholdsregal: preparations to prevent assassination, ranging from apprehending the assassin, protecting the mark, or actions to locate and neutralize the assassin, incarceration, distraction, or death) to declaring Snigmordforsog against the person who claimed it first, thus one target may declare intent to assassinate the person who made them a target.
Should the person who declared Snigmordforsog be slain by assassination, their existing claims are rendered void, and those who are acting on them, assassins, mercenaries, etc, are required to stand down from their pursuits, but must be paid a fraction of their services, typically 1/10 of the cost of the assassination.
To perform deception in the declaration of Snigmordforsog, having another declare the target so as to protect oneself from counter-declaration, or to declare snigmordforsog without a proper amount of time to prepare forholdsregal, such as making the claim the moment the assassin is in place to deliver the death blow, marks the person who makes the Snigmordforsog as a Fejhedforsog, a coward behind the blade. Being declared fejhedforsog is a step above being exiled or marked an outcaste. Anyone may raise weapon to such a coward and end them without declaring snigmordforsog or face consequences for committing murder.
Other terms
Barnmordforsog - declaring assassination against someone dramatically beneath your station. If a person cannot reasonably make forholdsregal against their assassin, it is considered poor form. A noble could not declare snigmordforsog against a commoner, as there is no way a commoner could prepare an adequate forholdsregal. Also the term is used for when snigmordforsog is declared against a child, or someone who isn't capable of preparing the forholdsregal on their own. This is strongly frowned upon, and typically the only way children are targeted is if the would be assassin in another child, both of whom are from noble or royal station. This often prevents war and disputes or inheritance among multiple children. In some situations, it might even be expected.
Kongemordforsog - the foolish practice of declaring assassination against someone drastically above your station. Typically a bad idea as this rendered the higher station person a free hand to defend themselves, and to declare counter-snigmordforsog against their would be assassin. Typically this is seen as an act of protest, or a way to weaken a powerful person as multiple kongemordforsogs will call for multiple forholdsregals, and contracts to eliminate those claimants. Should someone succeed in Kongemordforsog, they assume the patents and titles of the person slain. Should someone declare assassination against the King and actually succeed within the boundaries of the snigmordforsog, they become the new King.