Actus reus
Etymology
A Latin phrase meaning "guilty act," from actus, "an act, a doing" (from agere, "to do, to drive"), and reus, "guilty, accused." It is the twin of mens rea in the maxim that a crime needs both a wrongful act and a wrongful mind. It names the external, physical element of an offense.
noun phrase · /AK-tus-RAY-us/
The physical act or conduct that makes up a crime, as opposed to the mental intent behind it.
What it names
The "what actually happened" half of a criminal charge — the deed itself, which must be proved before intent even comes into play.
Example
The prosecution proved the actus reus easily; the fight was entirely over whether he had meant to do it.
Related idea
Actus reus is the physical deed; mens rea is the mental intent, and a conviction usually demands the two coincide.
See also