An obstacle is an object that makes it difficult for you to go where you want to go, because it is in your way.
双语例句
例： Most competition cars will only roll over if they hit an obstacle.
多数赛车在撞到障碍物时才会翻车。
例： He left her to navigate her own way round the trolleys and other obstacles.
他留下她独自在手推车和其他障碍物中间穿插行走。