1. (noun)obstacle, obstruction something immaterial that stands in the way and must be circumvented or surmounted
"lack of imagination 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"
2. (noun)obstacle an obstruction that stands in the way (and must be removed or surmounted or circumvented)