Cotemporaneous is an uncommon word that means contemporary or existing at the same time. There are several synonyms for cotemporaneous that can be used to convey the same meaning, such as contemporaneous, synchronous, simultaneous, coexistent, and concurrent. These words are often used to describe events that occur at the same time or individuals who lived during the same time period. Other synonyms include contemporaries, coevals, and peers. It is important to note that while these words have similar meanings to cotemporaneous, they may have slightly different connotations or contexts in which they are used. Nonetheless, these synonyms can be used interchangeably to convey the idea of being existing or occurring at the same time.