The word "un derived" doesn't have common synonyms in modern English, because it is a relatively obscure term. However, depending on context, a few possible replacements may include "invented," "created," "concocted," or "fabricated." These words generally describe the production or construction of something, which is not what "un derived" implies. Another option is to use the phrase "not derived," which means the same thing but is easier to understand for most readers. Overall, finding synonyms for obscure words can be challenging, but there are often alternatives available if you consider the context and meaning of the original word.