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"
an obstruction that stands in the way (and must be removed or surmounted or circumvented)
"The fallen tree blocking the trail was a serious obstacle we had to clear before continuing our hike."
Something that impedes, stands in the way of, or holds up progress
"The sudden storm became a major obstacle to our hiking plans, forcing us to turn back before we reached the summit."