Most employees have to stop (4)
I believe the answer is:
stem
'stop' is the definition.
(stem can mean to stop or interrupt)
'most employees have' is the wordplay.
'have' indicates the answer is hidden within the clue.
'STEM' is hidden within 'most employees'.
'to' is the link.
(Other definitions for stem that I've seen before include "Restrain the flow of" , "Main upright of a ship's bow" , "Axis" , "Stalk - check" , "Staunch (flow)" .)