The employees sat around being very noisy (5)
I believe the answer is:
staff
'the employees' is the definition.
(I've seen this before)
'sat around being very noisy' is the wordplay.
'around' indicates anagramming the letters.
'being very noisy' becomes 'ff'.
'sat' is an anagram of 'sta'.
'sta'+'ff'='STAFF'
(Other definitions for staff that I've seen before include "Man" , "Take a rod to the personnel?" , "Stick of authority" , "Body of teachers" , "Post - office workers" .)