obstacle

Still, Liu notes, “In China, policy is one thing, practice is another. There have been a lot of obstacles.”

Certain picks have proven contentious and may face obstacles.

The shortcomings of "Dune: Prophecy" are akin to the obstacles typical of most Herbert adaptations — sprawl is the mind-killer, not fear.

Then there are obstacles of the self-imposed variety, including Trump’s choice to head the EPA: former Rep. Lee Zeldin of New York, whose main qualification seems to be loyalty.

It's a common sight -- ants marching in an orderly line over and around obstacles from their nest to a food source, guided by scent trails left by scouts marking the find.