Undifferentiation refers to a lack of distinction or differentiation between different things or entities. Some synonyms for undifferentiation include homogeneity, similarity, uniformity, conformity, and sameness. Homogeneity refers to the quality of being uniform or consistent, while similarity refers to the resemblance of two or more things. Uniformity may also denote a lack of difference or variety in something. Conformity refers to adherence to established norms or standards, while sameness suggests a lack of distinction or variety. Therefore, these synonyms are useful in expressing a lack of differentiation in various settings, such as in objects, people, and ideas.