Door, open -- so ___? Profit! (6)

I believe the answer is:

income

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'profit' is the definition.
(thesaurus)

I can't explain the remainder of the clue.

(Other definitions for income that I've seen before include "What do you make" , "Money received as wages, interest etc" , "Money from investments or for work" , "See 12" , "Money received on which tax is payable" .)

I've seen this clue in The Telegraph.

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