Key difference: The words obstacle and impediment are types of hindrances. Obstacle means obstruction barrier in progress, while impediment means obstruction barrier in any task.

An obstacle means a ‘thing that blocks one's way or prevents or hinders progress’.

An obstacle is something which provides a block to any progress. It provides difficulty in the ongoing progress of a thing. Obstacle acts as a disability while doing work. An obstacle is said to be some immaterial block to anyone’s progress.

Obstacle stops an object which is said to be in motion. It reduces the speed of the object. It sometimes also acts as a challenge which should be overcome. It makes the progress slow. Sometimes we say that our work was not completed due to some obstacles, that is, the obstacles are hindrances in our work. They provide a sort of break in the scheduled work.

An impediment means ‘any hindrance or obstruction in doing something’ or ‘any defect in a person's speech, such as a lisp or stammer’.

Medically, an impediment is especially said to be a physical hindrances, such as a lisp or a stammer. They act as a barrier in between the completion of any object. There are interferences while performing a task.

It is commonly related to the organic defects. In medical terms, these are also used for psychological problems. They are said to be long-lasting hindrances. An impediment is something which is used in expressing the disability like stammering (a speech impediment), shivering (a balance impediment), etc.  This term is also used legally.

Comparison between Obstacle and Impediment:

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