What is the legal term for the unjust killing of another human without premeditation?

The legal term for the unjust killing of another human without premeditation is known as manslaughter. This term refers to situations where an individual causes the death of another through negligent or reckless actions or during a state of provocation where they did not intend to kill. Manslaughter is distinct from murder charges because it lacks the element of premeditation or intent to kill which is required for murder convictions.

In the context of the choices provided, first degree murder involves deliberate planning and intent to kill, while second degree murder implies malice and intent but not premeditated actions. Voluntary manslaughter, a specific type of manslaughter, typically occurs in the heat of passion or as a response to provocation, and still implies a level of intent, albeit less than that required for murder. Thus, the most accurate term for an unjust killing without premeditation in this context is simply manslaughter.