Once more making a profit (5)
I believe the answer is:
again
'once more' is the definition.
(synonyms)
'a profit' is the wordplay.
'profit' becomes 'gain' (synonyms).
'a'+'gain'='AGAIN'
'making' is the link.
(Other definitions for again that I've seen before include "return" , "Repeatedly" , "Predictably perhaps" , "Ocne more" , "second term" .)