Here are the steps on how to remove Words With Friends from your Instant Games list:
 
On your PC through Facebook Messenger:
 
  1. Locate Words With Friends on your list of messages on Messenger.

     
  2. Tap on the 3 dot icon

     

  3. Click on "Mute notifications"

     
  4. Click on "Message and call notifications" then select "Next"



On Mobile:
 
The only way that you can remove Words With Friends Instant Games on your device is by muting the conversation sent by the app. Here are the steps:
 
For iOS:
 
  1. Locate Words With Friends on your Facebook Messenger list.

  2. Tap the Words with Friends Profile

  3. Tap on Mute Button


  4. Select Message Notification

     

For Android:
 
  1. Locate Words With Friends on your list of games / messages.

     
  2. Tap the information icon on the top right corner



  3. Tap on Mute Button



  4. Tap on "Mute message notifications"



  5. Select "Until I turn it back on" and press OK.

Note: If you play another game with a friend, this option automatically goes back to Unmute.
 
Should you wish to Block/Ignore Messages and Leave Group from Instant Play, here's how:
 
On your PC through Facebook Messenger:
  1. Locate Words With Friends on your list of messages on Messenger
     
     
  2. Tap on the Gear icon on your message

     
  3. Select "Ignore messages" or "Block" from the dropdown
 
On Mobile:
 
For iOS:
 
Tap the name of your opponent or group chat, then select the following:
 
 
For Android: