This is the place at which a man starts again (4)
I believe the answer is:
here
'this is the place' is the definition.
(I've seen this before)
'which a man starts again' is the wordplay.
'which' becomes 'h' (I can't explain this - if you can you should give a lot more credence to this answer).
'a man' becomes 'ed' (short for Edward).
'starts' means to remove the last letter.
'again' becomes 're' (prefix meaning 'again').
'ed' with its final letter taken away is 'e'.
'h'+'e'+'re'='HERE'
'at' acts as a link.
Can you help me to learn more?
(Other definitions for here that I've seen before include "Hither" , "Present - at this point" , "On this spot" , "final clue?" , "The present location" .)