What is a spam trap and how would I hit one?

A spam trap is an email address created or repurposed specifically to catch senders with poor list practices - there is no real person behind it, so any mail it receives proves you emailed someone who never opted in:

• Pristine traps - addresses never used by a human, planted purely to catch scraped or purchased lists.
• Recycled traps - once-real addresses, long abandoned, that providers reactivate as traps; they catch you when you keep emailing people who stopped engaging years ago.
• Typo traps - addresses like a common misspelling of gmail.com that catch lists collected without validation.
• Why it hurts - hitting a trap can damage your sender reputation immediately and, with some blocklists, get your domain listed.

You avoid spam traps the same way you avoid every deliverability problem: only email people who explicitly opted in, and remove the disengaged.