The word "endermic" is not a widely used term in the English language. As such, there are not many synonyms available for this word. However, there are several words that can be used to describe the same thing. For instance, the word "cutaneous" can be used to describe anything relating to the skin. Similarly, the word "dermal" can also be used to refer to something that relates to the skin. Additionally, the term "subcutaneous" is a suitable replacement for "endermic" in some contexts. "Epicutaneous" and "intradermal" can also be used in place of "endermic" in certain medical contexts.