When I 'Google' it on the Consumer side of the Equation, McAfee Web Advisor lists it as 'Unverified'? Quite possibly you may need to submit it for a review.
To explain it best ask Google:
DDoS is short for Distributed Denial of Service. DDoS is a type of DOS attack where multiple compromised systems, which are often infected with a Trojan, are used to target a single system causing a Denial of Service (DoS) attack.
You should really be asking your hosting company and/or Wordpress for a better explanation and how to avoid it. The consumer products aren't designed to protect websites.