obstacleobstacle /ˈɑbstɪkəl/ noun 1 
something that blocks a road or passage so that people or things cannot go through► obstacle
something that blocks a road or passage so that people or things cannot go through► obstacle something that blocks a road or path so that you must go around it, over it, under it, etc.: The soldiers have to climb over or go under all the obstacles as they run around the course.
► barrier a fence or wall that stops people from entering a place: A barrier was put up to stop cars from entering the street.
► obstruction something that blocks something such as a road or passage completely so that nothing can go past or through: Doctors had to operate to remove the obstruction in his bowel. A tree fell, causing an obstruction in the road.
➔ see wall2 something that makes it difficult for someone to do or achieve something► obstacle something that makes it difficult for someone to do or achieve something, but that does not make it impossible to achieve it: There are many obstacles to peace in the region. The team had to deal with many obstacles this season, but they still went to the finals.
► stumbling block stumbling block means the same as obstacle but sounds more informal: The biggest stumbling block for students is usually finding enough money to go to college.
► barrier a situation or problem that stops someone from doing something: The law says that being disabled cannot be a barrier to getting a job.
► obstruction the act of preventing or delaying a legal or political process. Obstruction is used especially in the phrase obstruction of justice, when someone does something to make it hard for the police or other officials to find out about a crime: He destroyed the documents about the crime, and was later accused of obstruction of justice in court.