The phrase "complex word" can be substituted with a variety of synonyms. These include: advanced terminology, compound term, intricate expression, complicated phrase, convoluted word, challenging vocable, sophisticated lexicon, intricate locution, elaborate dialogue, and dense lexeme. Each of these synonyms conveys a similar meaning to "complex word," referring to language or vocabulary that is difficult to understand or contains multiple components. These words are often used in academic or technical writing, where precision and clarity are essential. Regardless of the term used, it's important to clearly define any complex vocabulary to ensure that readers have a full understanding of the subject matter.