A profit, not for the first time (5)
I believe the answer is:
again
'not for the first time' is the definition.
(I've seen this in another clue)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for again that I've seen before include "Furthermore" , "Moreover - a second time" , "Here we go ___" , "Ocne more" , "Next time" .)