Profit trap involves American (4)
I believe the answer is:
gain
'profit' is the definition.
(I know that profit can be written as gain)
'trap involves american' is the wordplay.
'trap' becomes 'gin' (gin trap is a kind of animal trap).
'involves' means one lot of letters goes inside another.
'american' becomes 'a' (common abbreviation - e.g. in organisation names).
'gin' enclosing 'a' is 'GAIN'.
(Other definitions for gain that I've seen before include "Benefit; increase in value" , "reward" , "Earn, profit" , "Obtain, secure" , "Pick up" .)