An other way is to "take a break" of this person. He/She will no longer see what you post on Facebook but you will still be friends and you can still talk to each other using the chat function.
To get this option you first go in the menu at the top of the persons profile. Here you chose for blocking the person.
Now you can chose to confirm or, and this is what we need, click on "Take a break"
Next up, you have to choose "See options" for Limit What <<Name>> Will See.
To undo this setting you have do the same steps but select the first option.



