This is traditional money like dollars, pesos, pounds, euros, yuan, and many others. By definition 'fiat' money means it is declared by the issuing state that the currency is to be this or that. The state, or the issuing body, controls the money supply and many economic functions of a fiat currency. In comparison to a CDBC, which can also be issued by a state, a fiat money is likely physical and not held on code or a blockchain.
Do you even save your fiat anymore? I've spent most of mine on crypto and living at this point.
Actually, my fiat savings went down went printer go brrrr.. So I moved everything and staked!!