The Block Player feature allows you to deal with toxic or verbally abusive behavior. Blocking Players will prevent their messages from reaching you. All you need to do is to open their Profile and select Block. You will not receive any inbox messages or alliance invitations from the blocked player. Additionally, chat Threads created by the player you blocked will be displayed with a red overlay and will contain no text.
You can manage the Players you blocked and unblock them in your Blocked List, that can be accessed from the main command interface > >More > Blocked List. You can use the Unblock button should you wish to undo the block.