a legislator who gives long speeches in an effort to delay or obstruct legislation that he (or she) opposes
"The senator launched a filibuster against the new budget bill, speaking for twelve hours straight to prevent it from reaching a vote."
(law) a tactic for delaying or obstructing legislation by making long speeches
"During the Senate debate, the senator launched a marathon filibuster to prevent the new budget bill from reaching a vote."
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.
"During the turbulent 1850s, many American filibusters boarded ships bound for Cuba with the intent of overthrowing local governments by force to seize their lands."
obstruct deliberately by delaying
"The senator launched a marathon speech to filibuster the bill and prevent it from reaching a vote before recess."
To take part in a private military action in a foreign country.
"The intelligence report warned that rebel groups planned to filibuster the neighboring nation's capital by seizing key bridges and tunnels overnight."
The word comes from the Spanish term filibustero, meaning "pirate," which itself traces back to the Dutch phrase vrijbuiter for "freebooter." This original Dutch combination of words for "free" and "booty" was altered slightly in French before entering English.