### Clue: Former coppers judge dealers' standard (8,4)
### Answer: EXCHANGE RATE 
 ### Explanation: Definition: dealers' standard
  EX(former, as in ex-spouse) CHANGE(loose coins in your pocket, presumably pennies or cents, called coppers as copper is what they used to be made of) RATE(to judge,assess)
Defn:  The standard by which one currency is measured against another, ie. the exchange rate, which foreign exchange dealers use in their work.