DNM stands for "Do Not Mail" which is a term used to indicate that a person does not wish to receive any mail from a specific source. Synonyms for the term DNM include "opt-out", "unsubscribe", "stop mail", and "cease correspondence". These terms are commonly used in the context of email marketing and direct mail campaigns where companies seek to send promotional material to their customers or potential customers. When a person opts-out or unsubscribes, it means they no longer want to receive such promotional material. Similarly, when they ask for mail to stop or for correspondence to cease, they are asking to be removed from the company's mailing list.