Clue: A gold plate conducting current with variable physical property (7)
Answer: AGILITY
Explanation: Definition: physical property
 A + GILT(a gold plating/gold paint applied in a thin layer to a surface) **containing**(conducting) I(symbol for electric current in physics) **plus**(with) Y(in mathematics, a symbol for a quantity which can vary).
Defn: …, specifically the ability to physically move quickly and easily.