This term for a type of obstructionist comes from the Dutch for "freebooter" or "pirate"
[DOC] [TLE] Filibuster - definition of filibuster by The Free Dictionary [PAR] (Historical Terms) a buccaneer, freebooter, or irregular military adventurer, esp a 
... from Dutch vrijbuiter pirate, literally: one plundering freely; see freebooter].