something that blocks a road, passage, entrance, etc. so that nothing can go along it, or the act of blocking something in this way

There's some kind of obstruction on the railway tracks. 铁轨上有障碍物。

behaviour or actions that prevent something from happening or working correctly

They were charged with obstruction of the police/of justice (= preventing the police/law courts from doing their jobs). 他们被指控妨碍警方执行公务／司法公正。

in sport an occasion when one player gets in the way of another and so prevents them from moving freely

The referee said it was obstruction. 裁判判定这是阻挡犯规。