Noun
1. any structure that makes progress difficult
2. the state or condition of being obstructed
3. something immaterial that stands in the way and must be circumvented or surmounted;
"lack of immagination is an obstacle to one's advancement""the poverty of a district is an obstacle to good education""the filibuster was a major obstruction to the success of their plan"4. the act of obstructing;
"obstruction of justice"5. getting in someone's way