1. Literally, to sit as a juror in order to decide if someone is guilty of something or not. The defendant's notoriety made it difficult to find anyone who could sit in judgment of him without bias.

2. By extension, to make a judgment about someone for something they have done. The defendant's notoriety made it difficult to find anyone who could sit in judgment of him without bias.

3. To judge the merits of something. You shouldn't sit in judgment of video games if you've never tried them before.