Competence, like many legal English terms, has different meanings depending on the context in which it is used. Essentially, competence means the basic ability to do something or the ability to do something well.
Competence can also mean the quality of being real or true such as in the context of a document’s competence as evidence at a trial.
In addition, competence may describe the power of a court, authority or other official body to decide a legal case or to make an order or of a government to do something. Fundamentally, any legislation brought forward must be within the competence of the given legislative body.
Finally, competence may signify the ability to make legally binding decisions for oneself. For example, a person suffering from a mental illness may lack the necessary competence to enter into a contract, to get married, to write a will, or to stand trial, etc. In this respect, the word competency is used only when describing a person’s ability to stand trial, especially a criminal defendant. Otherwise, competence is the correct form of the word. The condition of not being able to make legally binding decisions for oneself may be referred to as lack of legal capacity, lack of capacity, lack of competence, or lack of legal competence.