Heads of section talk up department boss (4)
I believe the answer is:
stud
'boss' is the definition.
('stud' can be a synonym of 'boss')
'heads of section talk up department' is the wordplay.
'heads of' indicates taking the first letters.
The first letters of 'section talk up department' is 'STUD'.
(Other definitions for stud that I've seen before include "Stallion for breeding - fastener" , "kind of farm" , "Decorative round-headed nail" , "Farm for breeding horses" , "Part of a football boot" .)