Parliamentarian (noun)

1. A member of a parliament, esp. one with experience and knowledge of parliamentary procedure and rules.
2. A person who is expert in the rules and procedures of a legislative assembly.

Origin:

Mid 17th century: from medieval latin parliamentarius, from latin parlamentum (see parliament).

Examples:

1. He is a seasoned parliamentarian with years of experience.
2. She is a parliamentarian and also an expert on constitutional law.
3. The parliamentarian gave the Speaker advice on the parliamentary procedure.
4. The parliamentarian helped the members to understand the rules of the assembly.
5. The parliamentarian was appointed to advise the government on the legislative process.