Nuncle is a very uncommon term that is not widely known, and thus, it is not surprising that synonyms for the word are also uncommon. While many people may not be familiar with the word nuncle, it is generally understood to mean an affectionate nickname for one's uncle. Some synonyms that can be used in place of nuncle include unkie, unclekin, unclekins, or even simply, uncle. However, it's important to note that the word nuncle may be more personal and endearing than these other synonyms, as it reflects the unique and affectionate bond between an individual and their uncle.