The term "not differentiated" refers to a state in which things are not clearly distinct from one another. There are a variety of synonyms that can be used to describe this state, including undistinguished, indistinct, unremarkable, unexceptional, unidentifiable, and unrecognizable. Other options include vague, unclear, ambiguous, undefined, and unspecified. Each of these words provides a slightly different shade of meaning, but they all convey the sense that something lacks a clear and defining characteristic. Whether you are talking about people, objects, or ideas, there are many ways to describe a lack of differentiation, and each word can help you express your meaning with greater precision and nuance.