The term "co-father" is a relatively new term in the English language used to refer to fathers who share the duties and responsibilities of parenting with their partners. However, there are other words that can be used to describe this same concept. One of the common synonyms for co-father is "co-parent," which highlights the shared parenting responsibilities between two individuals. Other synonyms include "daddy partner," "parenting partner," "father figure," and "fathering partner." These words are useful in situations where co-father may not be as appropriate, and they highlight the vital role played by both parents in raising a child.