What is the term for a character that is not highly developed?

A character that is not highly developed is referred to as a flat character. Flat characters are typically one-dimensional and have only a few traits or characteristics. They often serve a specific purpose in the narrative, such as providing support to the protagonist or representing a particular theme or idea. These characters are usually predictable, as they do not experience significant growth or change throughout the story, making them less complex compared to round characters, who are multi-faceted and undergo development.

In contrast, round characters are fully developed and exhibit a range of emotions and personality traits, often evolving throughout the story. Static characters remain the same and do not undergo any significant change, while dynamic characters experience growth or transformation. Thus, the term that defines a character with limited development is indeed a flat character.