obstruction

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Something that obstructs; an obstacle.
• noun The act of obstructing.
• noun The condition of being obstructed.
• noun Sports The act of impeding another player in violation of the rules, as when a player impedes the progress of an opponent not in possession of the puck in ice hockey.

from The Century Dictionary.

• noun The act of obstructing, blocking up, or impeding passage, or the fact of being obstructed; the act of impeding passage or movement; a stopping or retarding: as, the obstruction of a road or thoroughfare by felled trees; the obstruction of one's progress or movements.
• noun That with which a passage is blocked or progress or action of any kind hindered or impeded; anything that stops, closes, or bars the way; obstacle; impediment; hindrance: as, obstructions to navigation; an obstruction to progress.
• noun Stoppage of the vital function; death.
• noun Systematic and persistent factious opposition, especially in a legislative body; factious attempts to hinder, delay, defeat, or annoy.
• noun Synonyms Difficulty, Impediment, etc. (see obstacle), bar, barrier.

from the GNU version of the Collaborative International Dictionary of English.

• noun The act of obstructing, or state of being obstructed.
• noun That which obstructs or impedes; an obstacle; an impediment; a hindrance.
• noun Poetic The condition of having the natural powers obstructed in their usual course; the arrest of the vital functions; death.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun The act of obstructing, or state of being obstructed.
• noun That which obstructs or impedes; an obstacle; an impediment; a hindrance.
• noun The condition of having the natural powers obstructed in their usual course; the arrest of the vital functions; death.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun something immaterial that stands in the way and must be circumvented or surmounted
• noun getting in someone's way
• noun any structure that makes progress difficult
• noun the act of obstructing
• noun the physical condition of blocking or filling a passage with an obstruction