To obstruct means to block or get in the way of something, preventing it from moving forward or working properly. When a fallen tree obstructs a hiking trail, hikers can't get through until someone clears it away. When someone parks their car in front of a fire hydrant, they're obstructing access to equipment firefighters might need in an emergency.

Obstruction can be physical, or it can involve blocking progress or plans. A student might obstruct a group project by refusing to share necessary information. In sports, a player commits obstruction when they illegally block an opponent's movement, like a soccer player who steps in front of an opponent without trying to play the ball.

The word carries a sense of interference: something that should flow or proceed smoothly gets stopped or slowed down. Traffic gets obstructed by construction. Justice gets obstructed when someone destroys evidence or lies to investigators. A view gets obstructed when someone tall sits directly in front of you at the movies.

When you obstruct something, you actively prevent it from happening the way it should, creating a barrier that stops normal movement or progress.