The word 'filibuster' derives from a Dutch word meaning 'freebooter' or pirate.
Notes on verification
Multiple independent etymological references (Etymonline, Merriam-Webster, Wiktionary, NPR) agree on the Dutch 'vrijbuiter' origin, transmitted through French and Spanish before entering English.
Sources
- Filibuster, cloture: US Senate rules featured in abortion debate | Politics News | Al Jazeera (aljazeera.com)
- https://www.etymonline.com/word/filibuster (etymonline.com)
- https://www.merriam-webster.com/wordplay/filibuster-word-history-origin (merriam-webster.com)
- https://waywordradio.org/filibuster-freebooter/ (waywordradio.org)
- https://www.npr.org/2005/05/18/4656990/history-of-the-word-filibuster (npr.org)