When you hide a friend:
• You can still receive chat messages from them.
• They won't appear in your friends list, and will be moved to the Hidden users list.
• You'll see their profile and Timeline updates.
Hiding a user doesn't remove them completely as a friend or friend recommendation. To do so, please see the following article:
To hide a friend:
1. Tap the Friends tab.
2. Tap and hold the name of the friend you want to hide.
3. Tap Hide > OK.
To unhide a hidden friend:
1. Go to More > Settings.
2. Tap Friends.
3. Tap Hidden users.
4. Tap Edit next to the friend you want to unhide.
5. Tap Unhide to display the friend again.
Note: It may take a while for the changes to take effect.
To archive a chat, please see the following article: