What does actus reus refer to in criminal law?

Actus reus, in criminal law, refers specifically to the physical act or conduct that constitutes a crime. This definition encompasses any voluntary action that leads to a prohibited outcome, which is why the answer highlighting "a voluntary act resulting in an illegal outcome" is correct. The concept emphasizes that for a crime to occur, there must be a demonstrable action or failure to act (in certain circumstances) that breaches a law.

The other options focus on different aspects of criminal law. The intent behind committing a crime relates to mens rea, which deals with the mental state of the defendant and not the physical act itself. Awareness of one's illegal actions pertains to culpability but does not define actus reus directly. Lastly, while omissions can be relevant in some criminal cases, they form a separate aspect of actus reus, not its overall definition. Thus, the focus on voluntary acts resulting in illegal consequences correctly encapsulates the essence of actus reus in the context of defining criminal conduct.