Head of department chasing female cast (4)
I believe the answer is:
shed
'cast' is the definition.
(shedding is a kind of casting)
'head of department chasing female' is the wordplay.
'head of' says to take the initial letters.
'chasing' means one lot of letters go next to another.
'female' becomes 'she' (I've seen this before).
The initial letter of 'department' is 'd'.
'd' put after 'she' is 'SHED'.
(Other definitions for shed that I've seen before include "Cast, wooden building" , "In which tools may be" , "Get rid of - garden building" , "that may be at bottom of garden?" , "Outbuilding for storage" .)