For whom the bell tolls (4)
I believe the answer is:
thee
'for whom the bell tolls' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for thee that I've seen before include "You in the olden days" , "Archaic form of 'you'" , "Poetically you" , "You (arch.)" , "Old objective second person singular" .)