can they keep your tax refund if you have a judgement against you
It depends on who "they" are nd what they do to secure the taxx refund, but yes, generally a judgment holder could attach a tax refund, but it is very uncommon.
Workers' Compensation Lawyer
If you have a judgment against you its time to consider bankruptcy and go meet with a bankruptcy attorney to see what your options are. You do not want to have to worry all the time if your taxes are going to be seized, or a bank account, or worse yet your paycheck garnished. Take some action to resolve your financial situation as it will give you some final relief.
For more information, visit www.freebankruptcyinformation.info or checkout my legal guides regarding this topic posted on my AVVO profile.
Legal Information is Not Legal Advice
My answer provides information about the law based on the limited information provided in the questions asked and is not intended to be legal advice. The law differs in each jurisdiction and may be interpreted or applied differently depending on the location or situation. I highly recommend that you consult with an attorney to discuss the specific details of your situation so you can get legal advice tailored to your specific circumstances. The information in my answer is for educational and information purposes only, and is not legal advice or legal opinions. The answer provided to the question asked does not constitute a lawyer-client relationship.
If you are talking about a creditor garnishing a tax refund, the answer is generally a state tax refund can be garnished by a creditor, but not a federal refund. However, there are two exceptions. A federal tax debt may result in a refund being seized by the IRS and applied to the debt, and unpaid child support may result in a garnishment by the friend of the court to pay the child support.