The term "coinage of the brain" refers to the creation or invention of a new word or phrase. However, there are several synonyms for this phrase that can be used to convey the same idea. For example, "neologism" is a term used to describe a new word or phrase that is coined or created, especially in language or culture. Another synonym for "coinage of the brain" is "lexicological innovation." Similarly, "verbal invention" or "lexical creativity" can be used to describe the process of creating new words or phrases. Ultimately, these synonyms all refer to the same concept of inventing a new word or phrase through the power of the brain.