Spam traps, also called a “honeypots”, are email addresses created (or re-activated) by ISPs specifically to lure spammers. In many cases, the only way to acquire the address is through an automated email address harvesting process.
Spam traps are important because so many large ISPs, spam filter providers and Domain Name System blacklists use them. In short, sending an email to a spam trap can lead directly to being blacklisted by the organization that set up the trap. Remember that blacklisting can ruin a business’s reputation and halt further email deliverability.
This article from our Support Help Center goes into specific details about spam traps.