I am thinking that, in certain circumstances, it could be considered defamation, although it is more likely an invasion of privacy action you would want to consider.
Defamation covers words that injure a reputation or, in some cases, cause emotional distress. If a list of donors, say, is published, and your name is listed as having donated to a group or organization, and this particular group or organization is one where your connection to it could cause you harm in the workplace, you may have a legitimate cause of action, although it may more legitimately be an invasion of privacy action (putting a person in a false position or light in the public eye) than a defamation action, depending on what was published.
If your reputation is, for instance, tied to Planned Parenthood and the donation is, say, to a Right-to-Life group that has targeted Planned Parenthood clinics for their stand on abortion rights, this could affect your ability to counsel pregnant women.This may not be a great example, but perhaps you get the idea.
So, to my way of thinking, yes, it could be libelous and it could be considered an invasion of privacy, potentially. But more details from you would be necessary.