Those in university hospital department following boss -- head of surgery (8)
I believe the answer is:
students
'those in university' is the definition.
'hospital department following boss head of surgery' is the wordplay.
'hospital department' becomes 'ent'.
'following' means one lot of letters go next to another.
'boss' becomes 'stud' ('stud' can be a synonym of 'boss'**).
'head of' suggests taking the first letters.
The first letter of 'surgery' is 's'.
'ent' after 'stud' is 'student'.
'student'+'s'='STUDENTS'
(Other definitions for students that I've seen before include "Trainee medics possibly" , "School or university attendees" , "Pupils or apprentices" , "Pupils, learners" , "Learners as at school" .)