Noncomplementing refers to a situation where two things do not fit or complement each other. There are several synonyms for noncomplementing, including mismatched, incongruous, incompatible, and unfitting. Mismatched refers to two things that do not go together because of a lack of similarity or compatibility. Incongruous is used to describe things that are mismatched or out of place. Incompatible highlights a lack of adaptability or the inability to work together. Unfitting describes things that do not match or suit each other. All of these words can be used interchangeably with noncomplementing to depict a situation that does not fit well or is not suitable for each other.