Fila what?

The pirates started it. The Dutch had a term for them: vrijbuiter, which sort of translates into English as freebooter, ie, someone free of national allegiance who sought booty. Pretty soon other languages had borrowed vrijbuiter as well. The French translated it as filibustier, the Spanish filibustero. We Americans took it from the Spanish and got the word "filibuster".
Why Spanish? Because a new kind of filibuster was taking place in parts of North and South America that spoke Spanish in the 1800s. Citizens of the United States were involved. This new piracy occurred on the land rather than at sea, and it involved capturing whole countries rather than ships. In the 1820s, after the revolutions in Latin America had swept most of the region free of Spanish control, the weak new governments provided tempting opportunities for adventurers seeking to do business, bring democracy, or just buy the place out.
One such adventurer was William Walker of Nashville, Tennessee(and later San Francisco). Walker supported slavery and thought that the best way to keep slavery going was to take over the rest of the continent with slave territories. He tried unsuccessfully to capture lower California in 1853-1854. He was more successful a couple of years later when he installed himself as president of Nicaragua in 1856. The USA was not so amused. A naval force was sent to dispatch him of his new purchase the next year. He died in 1860 while attempting to conquer all of Central America. Now there's a guy with hutzpah.
By the early 1850s, this adventuring was much discussed in Washington, D.C. In January of 1853 one U.S. Senator was recorded as accusing another of "filibustering" against the United States. The word then began to be applied to a particular tactic: taking advantage of the Senate's privilege of unlimited speech to delay action on a bill.
Senators are allowed to speak at length on any topic, and for most of history, they've been blabbing away. The word "bunk", as in, "That's a bunch of bunk!" was invented for politicians in the 1820s who ranted on. In 1828 a newspaper article said, "Talking to Bunkum is an old and common saying at Washington, when a member of congress is making one of those humdrum and unlistened to "long talks" which have lately become so fashionable." Not a lot has changed, eh?
Early on in the history of our country, the senate decided that it would take a 2/3 vote to shut these fellows up. This is just a rule of the senate, and has nothing to do with a free country, the constitution, apple pie, or baseball. It provides a way for the minority party, a small group, or even one determined individual to prevent the majority from having its way.
In middle of the 1900s, filibustering was used by democrats as a way to prevent civil rights legislation from passing. After Rosa Parks helped MLK kick off a very successful boycott of the bus system, and after JFK was assassinated, LBJ introduced civil rights legislation in the senate, a crowning moment for his political career. Former KKK member Robert Byrd (yep, _that_ Robert Byrd) spent 14 hours on the senate floor arguing against the civil rights bill in 1964, saying it abrogated principles of federalism. Byrd lost, and LBJ got tied up in indecisiveness in Vietnam and went down with the ship.
While laws have been filibustered, judges never have. The one argued-about exception is Abe Fortas in 1968. Fortas was an extreme liberal; Republicans and southern democrats argued for five days about his nomination, and a cloture vote failed. This seems to be the definition of a filibuster by any means. Whether or not a five-day debate with members of both parties not wanting a judge is the same as a minority party obstructing a nominee is open to debate. In my opinion, five Robert Byrds should not be allowed to prevent the business of the U.S. Senate no matter what state or party they come from and no matter the justification of their actions. Fortas had other problems, however, and resigned the following year resigned from the court because he had taken $20,000 from a private foundation.
"Filibuster" is a funny word, and it has a wild history behind it. Over the next month, if it comes out that Alito beat up his grandma, conquered Central America, and robbed ships at sea, perhaps a filibuster would be appropriate.