Gmail has a dedicated Filter tool that customizes what action to take on messages people send to you. You can use the Filter tool to redirect messages from an email address directly into your trash, blocking all messages from the address from ever appearing in your inbox. The sender is not notified when you block him.
Enter the email address you want to block in the Search field at the top of the screen.
Click the arrow at the end of the Search field.
Enter the email address in the From field if it's not there already. The email address may show up in the "Has the words" field first.
Click the Create filter with the search link in the bottom corner of the expanded search filtering dialog.
Place a check mark in the Delete It check box.
Click the Create Filter button to confirm you want to immediately delete all emails that arrive from this sender.