A currency in which the ask price is more than 100 pips above the bid price. In this case, three digits will be displayed on the right side of the slash (in a given currency pair). For example, EUR/CZK 32.2565/ 890 indicates a weak quote currency (which is the Czech koruna).

Another example is USD/JPY 89.49/460 (here the weak quote currency is the Japanese yen).