Gmail is a robust online email service that allows you to create detailed contact lists, organize your inbox and prioritize the email you receive with labels and groups. However, if you're receiving unwanted mail from someone, you may want to block them altogether. Gmail's block feature works by filtering out the sender's incoming emails and circumventing them to an unseen folder--in this case, the "Trash" folder. To block an email address and make the sender aware that you've blocked the address, you must create a filter blocking the email address, then notify the sender with a follow-up email.
Block the Sender
Log in to your Gmail account. Visit gmail.com and enter the email address and password for the account from which you wish to block the sender.
Click the small blue "Create a Filter" link next to the "Search the Web" button near the top.
Type the email address you wish to block in the "From" field.
Click the "Next Step" button.
Check the box next to the "Delete" option. This will automatically move all the emails you receive from this email address to the trash. Gmail will block you from ever seeing these emails unless you read your deleted emails.
Notify the Blocked Sender
Click the "Compose Mail" button to create a new email.
Enter the blocked sender's email address in the "To" field.
Type a brief message letting the blocked sender know you have blocked all incoming emails from that email address and you will not see any replies or new correspondence the person sends.
Click the "Send" button to send the email. If the person replies from the same address, you will not see the emails.
To block incoming emails based on other criteria, such as the person's first or last name or the words in a signature line, enter those words in the "Has the Words" field when creating your filter.
If you send and receive your Gmail from a mail client such as Outlook, you can create special rules to block senders and to automatically respond with a notice you have blocked the email address each time the sender tries to email you.
Courtesy counts. While letting someone know you've blocked any of his incoming emails can be uncomfortable, doing so as respectfully as possible may help take the sting out of any perceived rejection, and may reduce the chances that the person will simply start emailing you from a completely different email address.