Constantin Nacu (June 29, 1844 – February 20, 1920) was a Wallachian, later Romanian politician. Born into a boyar family in Bucharest, he studied law at the University of Bucharest, later obtaining a law doctorate from the University of Paris. He entered the magistracy, first as a prosecutor and counsel for the Bucharest Appeals Court, and then in the private practice of law. In 1879, he was hired as a professor of civil law by his alma mater. He entered the National Liberal Party (PNL) in 1880. In 1882, party members began discussing modifications to the 1866 Constitution that would have the effect of weakening the Conservative Party's electoral strength. In the spring of 1883, an election was held for the legislature tasked with approving the modifications; it was then that Nacu won his