Yes, emails can be blocked:

• You can block a sender if you no longer wish to see their communications.
• Click Junk > Block Sender after right-clicking a message from the sender you want to block.
• The barred person can still send you email, but anything sent to your account from his or her email address is automatically sent to the Junk Email folder. If your administrator has enabled it, future mails from this sender will go to your Junk Email folder or End-User Quarantine.

Read More: How can you email large files?