filibuster

A tactic (such as giving long, often irrelevant speeches) employed to delay the proceedings of, or the making of a decision by, a legislative body, particularly the United States Senate.

(US) A member of a legislative body causing such an obstruction.

(historical) A mercenary soldier; a freebooter; specifically, a mercenary who travelled illegally in an organized group from the United States to a country in Central America or the Spanish West Indies in the mid-19th century seeking economic and political benefits through armed force.

To use obstructionist tactics in a legislative body.

To take part in a private military action in a foreign country.