The word "obstacle" means a barrier or hindrance that prevents something from happening or being done. It can be physical, like a rock or a wall, or abstract, like a belief or a lack of resources.
Examples:
- Physical obstacle: A mountain is an obstacle to a journey.
- Abstract obstacle: A lack of money is an obstacle to buying a house.
- In a sentence: "The heavy rain made it difficult to see, so the team had to take a different route."
Would you like me to explain it in a different way or give more examples?