A more thorough explanation:

Definition: De son tort is a legal term that means "by his own wrongdoing." It is a Law French term that is used to describe something that is wrongful.

For example, an executor de son tort is someone who takes on the role of an executor without being legally appointed to do so. Similarly, a trustee de son tort is someone who acts as a trustee without being legally authorized to do so.

These examples illustrate the definition of de son tort because they both involve someone taking on a role or responsibility that they are not legally entitled to. In doing so, they are acting wrongfully and can be held liable for any damages or losses that result from their actions.