What is the more widely used alternative term for Deferred Messages?

The term "greylisted" refers specifically to a process used in email filtering that temporarily rejects messages from unknown senders. When an email is greylisted, the receiving mail server will not immediately accept it; instead, it will send a temporary failure message back to the sender. This means that the email is essentially deferred for a short period, during which the sender's server must try to resend it. Once the sender's server retries after a certain amount of time, the email is then accepted if the sender is deemed legitimate.

This greylisting practice serves as a method to reduce spam by only allowing emails from known and reliable sources through after the initial rejection, effectively filtering out many unwanted messages right at the point of entry. This makes "greylisted" a widely recognized term in the context of deferred messages in email security, as it directly relates to how certain messages are handled when their acceptance is temporarily postponed.