Firefox permits you to temporarily disable any extension in the event that you don't want to uninstall it completely. Here are the steps to disable an extension:
Go to Extension Manager, right-click the extension, and then select Disable.
The extension should now be grayed out in Extension Manager.
To re-enable the extension, right-click the extension, select Enable, and restart Firefox.
To uninstall the extension, you can either right-click the extension or select the extension and click the Uninstall button at the bottom of the Extension Manager.