Unobstructed and Unopposed

Unobstructed adjective - Allowing passage without obstruction.

Unopposed and unobstructed are semantically related in unhampered topic. In some cases you can use "Unopposed" instead an adjective "Unobstructed".

Unopposed adjective - Not having opposition or an opponent.

Unobstructed and unopposed are semantically related in unchallenged topic. You can use "Unobstructed" instead an adjective "Unopposed", if it concerns topics such as unhampered.