No, I don't have any knowledge of Big Five psychometric scales. I was going by the dictionary definition. And if I knew you were using a more technical term I would have looked it up, and still thought it was not the same as meanness:

http://en.wikipedia.org/wiki/Big_Five_personality_traits#Agr...

The agreeableness trait reflects individual differences in general concern for social harmony. Agreeable individuals value getting along with others.

This is absolutely not the opposite of meanness. If Wikipedia is incorrect, please edit it. Note that unlike a YC comment, a Wikipedia edit will require a real citation.