trilemma
difficult choice from three options, each of which is (or appears) unacceptable or unfavourable
liberal paradox
in economic theory, the claim that no social system can simultaneously ① be committed to a minimal sense of freedom, ② always result in Pareto efficiency, and ③ be capable of functioning in any society
impossible trinity
statement in international economics that that it is impossible to have at the same time a fixed foreign exchange rate, absence of capital controls, and an independent monetary policy