Go into “settings” at the top right hand corner of the screen, then click the “privacy” button, then add this person to your “block list”.
you can ignore the friend request, block him or report him
go to settings- privacy settings- block list in the bottom right side-type in the persons name then select block person by there name
Just block people by adding him/her to your block list.
Log on through the Facebook home page and head to the “My Privacy” page (see Resources below). You can change privacy levels for almost every Facebook feature from this page.
List the person you want to block in the “Block People” box on the My Privacy page and click “Search.”
Browse through the results to find the person you want to block. The more common the name, the more people you will need to search through.
Click the “Block Person” link for the person you want to block. The person will no longer be able to see your profile, and you will not turn up in the person’s search results.
Hope it helps you. For more information