The word "posseman" is a noun that refers to a man who is part of a posse. A posse is a group of people, often organized by a sheriff or law enforcement, who come together to help catch a criminal or maintain order.
In more advanced contexts, you might encounter "posseman" in discussions about law enforcement history, where it refers to individuals who took part in community policing efforts in the past.
While "posseman" specifically refers to a male member of a posse, the term "posse" can also refer to any group of friends or associates (for example, "my posse" can mean my group of friends).
There are no specific idioms or phrasal verbs that directly involve "posseman," but the term "to call a posse" means to gather a group of people for a specific purpose, usually related to law enforcement.
In summary, a "posseman" is a male member of a posse, typically involved in helping to enforce the law or catch criminals.