active infinitive: to be in contempt (of court) passive infinitive: to be found/held in contempt (of court)

To commit

You can also commit contempt of court, as with other crimes

Most native speakers would not recognise the word "contemn" but I believe it exists. I'm not sure if it's really in current usage in legal practice. You might come across the term "contemnor" meaning the person who commits contempt. Jonathan's suggestions would certainly be more widely understood.