Plaintiff: a person who brings a case against another in a court of law. (noun)
I heard this word said by one of the people in my group while working on the presentation. I looked it up and got that definition. We were talking about the opposing lawyer who is claiming that Delia from the story Sweat is guilty. The opposing lawyer in this case is the plaintiff since he is arguing his claim and making a case out of it. I understood what the word meant by this example.