Spam trap
An email address used by ISPs and anti-spam services to catch senders with poor list hygiene.
A spam trap is an email address used by ISPs, anti-spam services (Spamhaus, etc.), or list-hygiene companies to detect senders with poor list-acquisition or hygiene practices. There are two main types: pristine traps (addresses created specifically to catch spammers, never used for legitimate signups) and recycled traps (real abandoned addresses reactivated as traps after a dormancy period).
Sending to a single trap once is rarely catastrophic. Sending to traps regularly puts your domain on public denylists, which causes most mail to most providers to be rejected outright. Recovery from a trap-driven listing is procedural (delisting requests) and structural (fixing the practices that caused the listing — usually purchased lists or stale list hygiene).
Spam traps are why list buying ends badly: purchased lists are saturated with traps because they've been sold many times, and trap exposure compounds with each send. The structural fix is opt-in list acquisition plus regular engagement-based list pruning.