detour
An alternate way you take when the usual path is blocked.
A detour is an alternate route you take when your usual path is blocked or unavailable. When construction workers close part of a highway, they put up signs directing drivers to take a detour around the work zone. If your normal walk to school is blocked by a fallen tree, you'd need to find a detour through a different street.
Detours can be frustrating because they usually make trips longer, but they're necessary when the direct route isn't safe or possible. Sometimes a detour even reveals a shortcut or an interesting place you wouldn't have discovered otherwise.
People also use detour as a verb: “We had to detour around the parade” or “The conversation detoured into talking about video games.” In this sense, it means straying from your intended direction or topic. A detour might add time to your journey, but it can still get you where you're going.