Which of the following best describes an unlawful arrest?

An unlawful arrest is best described as an apprehension made without legal justification. This means that the arrest is executed without a valid reason, such as a warrant, probable cause, or reasonable suspicion, which are legal standards necessary for making an arrest. For an arrest to be lawful, the officer must have legitimate grounds based on facts and the law; otherwise, the individual being arrested may have their rights infringed upon.

In the context of the other options, an arrest made with a proper warrant is lawful and adheres to legal requirements. An arrest based on flawed evidence could potentially be contested, but it does not necessarily classify as unlawful unless there is a total lack of justification. Similarly, an arrest made in self-defense pertains to situations involving reactive measures to threats and does not fall under the definition of unlawful arrest, as it assumes the presence of immediate danger requiring an arresting officer's intervention. Each of these factors underscores the importance of legal justification in determining the lawfulness of an arrest.