To block a WeChat friend:
1. Open Contacts and select the friend you want to block.
2. Tap into their profile.
3. Tap the「...」icon in the top right corner of the profile page, then toggle on「Block」.
Note:
Once blocked, you will no longer receive messages from that friend. If they try to send a message, they will be notified with: "The message is successfully sent but rejected by the receiver."
To view and unblock friends, go to「Me」>「Settings」>「Friends‘ Permissions」>「Blocked List」. Select the friend to unblock, tap into their profile, then toggle off the「Block」button.