A profit one more time (5)
I believe the answer is:
'one more time' is the definition.
(I've seen this in another clue)
'a profit' is the wordplay.
'profit' becomes 'gain' (synonyms).
(Other definitions for again that I've seen before include "'Another time, once more (5)'" , "Moreover - a second time" , "On the other hand" , "Anew" , "Ocne more" .)