You won’t find him in Rotherhithe (3)
I believe the answer is:
her
'you' is the definition.
(thesaurus)
'in rotherhithe' is the wordplay.
'in' indicates the answer is hidden within the clue.
'HER' is hidden within 'rotherhithe'.
'won't find him' is the link.
This may not be correct. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for her that I've seen before include "That lady's" , "Belonging to the woman" , "The woman's" , "That lady" , "Belonging to a female" .)