There are a few synonyms for the commonly used term "tax money". One such synonym is "government revenue", which refers to the income generated by the government through various means, including taxation. Another term that can be used in place of "tax money" is "public funds", which refers to money that belongs to the public or the government. Additionally, "federal funds" can be used to describe money collected by the federal government through taxes, as well as from other sources like grants and aid. Lastly, the term "internal revenue" can also be used as a synonym for "tax money", as it refers to the income generated by a country's internal taxation system.