inconvertible

不換　—　Institutions

The state of not being exchangeable for gold or silver.

5 Drachmai silver coin of George I — A photograph of the real thing this term names.

With every war or crisis, countries suspended convertibility. Many cases began with the promise of being "temporary" but never returned to it. All currencies used in the world today are inconvertible.

References

Gold Reserve Act of 1934 — Federal Reserve History　Signed on 1934-01-30. Transferred ownership of all monetary gold in the US to the Treasury and prohibited the redemption of dollars for gold.
Inflation – lessons learnt from history — Deutsche Bundesbank　The hyperinflation of 1923. The currency ceased to function as a means of payment and store of value, and was replaced by the Rentenmark in November 1923.

Only works and primary sources whose existence has been verified are listed.