Protect a worker who is accused (9)
I believe the answer is:
defendant
'is accused' is the definition.
(I've seen this in another clue)
'protect a worker' is the wordplay.
'protect' becomes 'defend' (defending is a kind of protecting).
'a worker' becomes 'ant' (worker is a type of ant).
'defend'+'ant'='DEFENDANT'
'who' is the link.
(Other definitions for defendant that I've seen before include "One charged" , "Against whom an action is brought in a law court" , "Person accused" , "The one before the court" .)