How To UnAuthorized Facebook App

Facebook App are applications or websites that has direct connection or access to your Facebook account. Before those applications were listed as one of your Facebook apps, you logged in and authorized the app by clicking on the allow button on blue background. These apps maybe websites that auto share your post on Facebook, game applications that you play with your Facebook friends, applications for Facebook messenger and so on.
To do this you need to first of all log in to your Facebook account, on your account or profile wall, navigate to your Account Settings  from the Facebook navigation top bar drop down option at the right hand side of the navigation bar. Click to drop down and link to your account settings page by clicking on the Account Settings option.
Now when the account page eventually loads and open, click on the App option from the left hand sidebar on the page.

After that, you will see all the list of websites and applications that you did authorized or allow to have access to your Facebook account. Look for the one you want to delete or unauthorized and click on the edit link attached to it. After the click, there will be a drop down at the bottom of the app you want to remove.
Among the displayed options that showed up when you clicked on the edit link, click the remove option to pop up the "Remove Facebok App Name?" dialog box where you need to take the final step. When this dialog box shows up, all you need to do is to click on the remove button on blue background to unactivated the application.

After the app removal the app will no longer have access to your Facebook account unless you reauthorize it.