Broker runs out of silver (5)
I believe the answer is:
agent
'broker' is the definition.
('agent' can be a synonym of 'broker')
'runs out of silver' is the wordplay.
'runs' becomes 'r' (cricket abbreviation).
'out of' indicates named letters should be taken away.
'silver' becomes 'argent' ('argent' can be a synonym of 'silver').
'argent' with 'r' taken away is 'AGENT'.
(Other definitions for agent that I've seen before include "who can act?" , "Sales rep" , "One employed to incite others to commit illegal acts" , "Actor" , "One acting on behalf of another" .)