Coadjutrix is a rare and old-fashioned word that refers to a female assistant or collaborator. As it is an uncommon term, there are not many synonyms that can replace it directly. However, several words can convey a similar meaning. For instance, words such as helper, assistant, associate, collaborator, co-worker, partner, and aide can serve as synonyms for coadjutrix. Each of these words describes someone who works alongside another person, providing support, assistance, or guidance. Additionally, other related terms such as deputy, substitute, understudy, and stand-in can also be used as synonyms for coadjutrix, depending on the context they are used in.