A more thorough explanation:

Concussionary is an old-fashioned word that means a person who uses their power or authority to force others to give them money or other things. It is a type of extortion.

There are no specific examples given for concussionary, but here are some examples of extortion:

• A police officer who threatens to arrest someone unless they give them money.
• A landlord who demands extra rent money from their tenants.
• A gang member who forces a business owner to pay them for "protection."

These examples illustrate how someone in a position of power or authority can use that position to intimidate or threaten others into giving them money or other things.