Hesitating to dismiss personal assistant on drugs (5)
I believe the answer is:
using
'on drugs' is the definition.
(I've seen this in another clue)
'hesitating to dismiss personal assistant' is the wordplay.
'hesitating' becomes 'pausing' ('pause' can be a synonym of 'hesitate').
'to dismiss' suggests deleting specific letters.
'personal assistant' becomes 'PA' (abbreviation).
'pausing' with 'pa' taken away is 'USING'.
(Other definitions for using that I've seen before include "Putting to a particular purpose" , "Employing" , "Utilising" , "having recourse to" , "addiction" .)