When someone (usually new to email who doesn’t know netiquette rules) is forwarding junk, a nice note asking them to remove your address from the forward list usually works and they stop forwarding to everyone. This method works best with former coworkers, family members, etc. Or just delete the message and forgot about it. If the address belongs to someone you don't want to be in contact with, reply to the sender and ask them to stop sending you email. If you use Outlook, the rules are applied as the message is downloaded which could be hours later. They’ll get the autoreply back immediately. If you choose to send an autoreply and your email provider supports server rules, create the rule on the server. Depending on the specifics of the situation, tell them that you will be configuring a rule to delete any messages they send in the future. While an autoreply will work with people you are acquainted with, it’s better to just tell the person to stop sending you email – simply reply to their next message and tell them you don’t wish to get email from them. Don't play games - ignore them and if they threaten you, file a police report. If your email provider supports server-based rules to reject messages, reject the message at the server, otherwise, create a rule to delete any messages they may send. If the "scary person" is someone you know or a stalker, and you don't wish to receive email from them, tell them not to send you messages in the future. When you reject a message while downloading it to your email client, you're adding to the problem and a savvy sender will know a fake reject from the real thing. Once the gateway SMTP email server (your email server) has accepted email for delivery, the message has been delivered. True rejection can only be done during the SMTP transaction. Most spammers do not process bounce messages or use valid email addresses, so you'd only be adding to the traffic your mail server needs to process. While there are some third party utilities that do send fake non-delivery reports to senders, it's pointless to do so. I hate going to my junk mail box to find stray messages only to find this scary person's emails there." Can I create a rule that if a person I'm blocking sends me email it will trigger an automated response that their email is rejected? Sort of like blocking callers. "I need to do more than just add addresses to my spam list.