To force stop an app on a Firestick, you can follow these steps:

1. From the Firestick home screen, navigate to the “Settings” option.

2. Select “Applications” from the list of options.

3. Scroll down and select “Manage Installed Applications.”

4. Find the app you want to force stop and select it.

5. Select “Force Stop” to stop the app from running. This will force the app to stop running and prevent it from using any resources on your Firestick.