Someone who systematically obstructs some action that others want to take.

synonyms: obstructer, obstructor, resister, thwarter.

Roget 710: opponent, antagonist, adversary; adverse party, opposition; enemy etc. 891; the other side; assailant.    oppositionist, obstructive; brawler, wrangler, brangler^†, disputant; filibuster [U.S.], obstructionist.    malcontent; Jacobin, Fenian; demagogue, reactionist^†.    rival, competitor.    bete noir [Fr.].    ... show more

Polish: obstrukcjonista