Yen in secretaries' salaries (4)
I believe the answer is:
pays
'salaries' is the definition.
(I know this)
'yen in secretaries'' is the wordplay.
'yen' becomes 'y' (resembles the symbol for the currency of Japan).
'in' indicates putting letters inside.
'secretaries'' becomes 'PAs' (personal assistants).
'y' put inside 'pas' is 'PAYS'.
(Other definitions for pays that I've seen before include "stumps up" , "Is profitable, country (Fr.)" , "Gives money (for goods, etc)" , "Coughs up" , "Hollande's country" .)