XF 1.5 What is DNSBL?

I generally wake up to a few entries in my moderation queue, which is working as I like - we use an Upgrade that lets me see a user's first post and, if it's spam, then I get rid of it and the user.

Today, I have an entry in Users, not just Moderation, and it says what's below. What is this trying to tell me, please?


<uname> <email_addy>
Today at 6:45 AM
Spam Log:
  • DNSBL matched
Thank you.

Please tell me if I _approve_ this user in the User queue they're now in, will I still see their first post in moderation?