Answer: In "The Great Gatsby", Jordan Baker is a flat character, while Jay Gatsby is a complex character.
Explanation:
It might be useful to compare 'flat' and 'complex' characters. A flat character is a character that does not change throughout the story. These characters often lack depth, and play a minor role in the main plot. Complex characters, (also known as round characters), are well-developed and are often in the center of the main plot.
Let us now take "The Great Gatsby", a 2013 movie which was based on Fitzgerald's famous novel of the same, as an example.
An example of a flat character would be Jordan Baker, a woman which Nick dates for a certain period of time. Neither does her character appear too much in the movie, nor does it change until the end of it. On the other hand, Gatsby himself is a complex character. He is involved in the main conflict, and the audience truly gets to know him throughout the movie. At first, he seems like a man who only cares about luxury and partying, while we later find out that he throws the parties only because he still loves his ex-girlfriend, and wants to get her attention.