The Oxford Thesaurus An A-Z Dictionary of Synonyms - obstructionn.

1) obstacle, barrier, bar, check, stumbling-block, hindrance, impediment, hurdle, hitch, snag, catch, bottleneck, limitation, constraint, restriction: The fallen trees created an almost impassable obstruction. 2) checking, stopping, cessation, proscription, forbidding, forbiddance; hindering, impeding, limiting, halting, slowing: The obstruction of the bill's passage can be blamed on the Tories.