The Boss is the head of the family. He or she gets a cut of all business and often rules as a dictator, but sometimes is elected. He is the head of the "Administration" that also includes the Underboss and Consigliari.
The Underboss is second in command and is being groomed to be the leader. He or she is in charge of the Capos and is a go-between for providing orders.
A counselor to the family that usually has a bit more prestige in the outside community that advises the Boss. Often they were lower in stature in the mob but is in a much stronger position due to placement in this advisory role.
A Capo runs a crew within a family. Usually there are a few of these crews in any family. They run their group independently but will take orders from the Boss if commanded. The crews also pay a portion of their proceeds up the ladder.
Soldiers are Made Men or "Confirmed" and operate on a crew but have no real authority. He can be referred to as a "Friend of Ours" implying mob credentials to others they are introduced to.
Associates are not Made Men and thus have a lower stature. They are "Connected" but not actually "In" the mob. These are people that either are hoping to become a Soldier or are simply along for the ride to gain income through mob activity. They can be an "Earner" but still not be officially a mobster.
To get in on "The Action" is to get a piece of illicit profits.
To be in the Books is to be considered to be a mobster.
To be Booked is to be arrested and charged with a crime
To be a Book or Bookmaker is to run a gambling operation.
Some have started to use these interchangeably though a Button Man is really supposed to be someone who kills for a living while a Bagman is really about picking up and delivering money.
This is someone who is greedy by keeping illicit proceeds rather than sharing with the Family. They fail to "Kick Up" part of the profits to the Administration.
Sometimes referred to as the Mob Aloha, it takes on many meanings. The most important and common is you are welcome but with the added meaning of being that it wasn't a problem. It also means a lot of other things such as something being unbelievable or unachievable.
Goomba is considered a term of affinity towards someone as a mobster while a Goomah (or sometimes Goomar) is a term referring to a mob mistress. Though the terms have really nothing to do with one another, people generally can mistake them due to the sounds not being that far apart.
These are terms for killing someone yourself. This is as opposed to giving someone a "Pass" which is to let them off the hook and not killing them in possibly what was a "Mock Execution" which refers to scaring someone to straighten them out.
This is outsources the job by paying someone else to commit the crime.
For a paid killer, a piece of work can be someone they are assigned to kill.
Earning credibility by having your first kill.
These are used in reference to what someone who was killed is doing.