ON TRIAL

adv. or adj. phr. 1. For testing or trying out for a time before making a decision. I was lucky that I had bought the machine on trial because I didn't like it and was able to return it. Mother bought a new dishwasher on trial and was trying it out before deciding whether to keep it. 2. In a court being tried for a crime before a judge or jury. John White was on trial for murder. Mary was on trial before the Student Committee for spoiling school property.