Sentence:  As they attempted to use the international press to their advantage, the <WSD>filibusters</WSD> were eager to counter any articles they perceived as misrepresenting their actions. ... [T]he <WSD>filibusters</WSD> took issue with what they called the "Boletinero de Costarica" and its outspoken condemnation of the <WSD>filibuster</WSD> presence in Nicaragua. ... Costa Rican periodicals were especially scorned by the <WSD>filibusters</WSD> for their constant rallying cries against the US usurpers. 
Meaning of the word marked with <WSD> tags:  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.