Article: Click here to go to the Facebook Settings page. You can also get to the Facebook page by clicking the ▼ in the top right corner, and then clicking Settings.  In the Block apps section, in the Block apps field, start typing the name of an app you'd like to block. When you see the app you'd like to block, click the app name to block it. If you want to unblock an app, click unblock next to the app you'd like to unblock.

What is a summary?
Login to Facebook. Go to the Facebook Settings page. On the Settings page, in the left sidebar, click Blocking. Block a specific app.