Pole working for tycoon (5)
I believe the answer is:
baron
'tycoon' is the definition.
(I know that tycoon can be written as baron)
'pole working' is the wordplay.
'pole' becomes 'bar' (both can mean a metal rod).
'working' becomes 'on' (on can mean working or activated).
'bar'+'on'='BARON'
'for' acts as a link.
(Other definitions for baron that I've seen before include "Minor nobleman" , "Lowest rank of British nobility" , "A born nobleman" , "Lowest title of peerage" , "Noble rank" .)