There may or may not be a problem. Wordorigins.org was once briefly given one of these warning labels by Google. Google was very responsive and removed it swiftly after I contacted them. In my case, there was no malware or security problem, and I’m not sure what prompted Google’s algorithm to flag it.
But an aggregator like Onelook.com is more vulnerable to this type of thing. All it takes is malware on one of the sites they aggregate.
If Onelook.com is on top of things, I’ll bet the warning disappears rather quickly.