Manslaughter is the unlawful killing or homicide of a human being without the premeditation or malice (malice aforethought) required for the criminal offense of murder.

Many states have two types of manslaughter: (1) voluntary manslaughter—the defendant intended to kill the victim, but did so in self-defense, or in the heat of passion and without premeditation, or the defendant was insane and did not understand that the killing was wrong; and (2) involuntary manslaughter—the defendant negligently or recklessly caused the death of another person—such as when a person is intoxicated while operating a motor vehicle and causes an accident that results in the death of another person.

Some states do not have separate criminal offenses for voluntary and involuntary manslaughter—these states may have the offense of manslaughter and identify certain aggravating factors that may enhance the penalties upon a conviction for manslaughter.

Manslaughter is a felony offense and may be punished by a lengthy prison term. Manslaughter laws are generally located in a state's statutes—often in the penal or criminal code.

In Hawaii, manslaughter is defined under Hawaii Revised Statutes Section 707-702. The state recognizes both voluntary and involuntary manslaughter. Voluntary manslaughter occurs when someone intentionally kills another person in the heat of passion or during a sudden quarrel without the intent to cause death, which would otherwise be murder. Involuntary manslaughter, under Hawaii law, involves the reckless causing of the death of another person. Manslaughter in Hawaii is classified as a Class A felony, which can result in a lengthy prison sentence upon conviction. The specific circumstances of the offense, such as the use of a weapon or the presence of aggravating factors, can influence the severity of the penalties. It's important to note that Hawaii law also includes a separate offense for negligent homicide, which addresses cases where the defendant's negligence leads to the death of another person.