An Email Suppression List is a collection of email addresses that should not receive marketing or transactional emails due to opt-outs, spam complaints, or compliance regulations. This list helps businesses maintain email reputation, reduce bounce rates, and comply with GDPR, CAN-SPAM, and other email laws. CRMs and email marketing tools like Mailchimp and ActiveCampaign automatically manage suppression lists to prevent sending emails to unsubscribed or inactive users. Implementing a well-managed suppression list improves deliverability, reduces legal risks, and enhances customer trust.