An act of defiance is when someone goes against  authority. In the book catching fire many characters do defiance or rebellion things.

                        A defiant or rebel thing Katniss did during the private session is hang a dummy and put Seneca Cranes name on it. This is defiant because this is bad to do.

                        One defiant thing Peeta did is. He drew a picture of rue at the interview and he lied. This is defiant because doing things about a dead tribute is bad.

                        The tributes hold hands to present united front. This is defiant because they are banning together. In their interviews they talked about how president snow is a jerk. This is rebellious because it helps the uprising by turning people against him.

                        One defiant thing Cinna did is. During the interview for the quarter quell Katniss was wearing her wedding gown. Cinna change the dress a bit when Katniss twirls. When she did she change to a mockingjay. This is rebel because the mockingjay is a sign of rebellion.

                        Of all these things Cinnas was the most defiant. I think it is because the mockingjay is a symbol of rebellion.