What the title says?

Rizal had to define the word filibustero to his German friend Ferdinand Blumentritt, who did not understand his use of the word in Noli Me Tangere. In a letter, Rizal explained: "The word filibustero is little known in the Philippines. The masses do not know it yet. I heard it for the first time in 1872 when the tragic executions (of the Gomburza) took place. I still remember the panic that this word created. Our father forbade us to utter it, as well as the words Cavite, Burgos (one of the executed priests), etc. The Manila newspapers and the Spaniards apply this word to one whom they want to make a revolutionary suspect. The Filipinos belonging to the educated class fear the reach of the word. It does not have the meaning of freebooters; it rather means a dangerous patriot who will soon be hanged or well, a presumptuous man." By the end of the nineteenth century, the word filibustero had acquired the meaning "subversive" in the Philippines, hence the book is about subversion.