The definition of manslaughter is an unlawful killing that doesn’t involve malice aforethought—intent to seriously harm or kill, or extreme, reckless disregard for life. The absence of malice aforethought means that manslaughter involves less moral blame than either first or second degree murder. An example of this would be if a man or woman comes home to find their spouse committing adultery and they killed the other party. As long as they didn't have a cool off period it is probably going to be manslaughter.
Involuntary manslaughter is a killing that is unintentional and results from recklessness or criminal negligence, or form of unlawful act that is a misdemeanor or low-level felony. An example of this would be a someone driving under the influence and hits another car killing people in the other car and killing someone inside their car.
These four levels of murder are important. They separate the level of murder to give the appropriate punishment. We wouldn't want a person who committed first degree murder going to jail for involuntary manslaughter and so forth and so on.There are arguments over what is murder and what is manslaughter but as of now murder is murder and manslaughter is