Negotiate to exclude profit (7)
I believe the answer is:
bargain
'negotiate' is the definition.
(I know that bargain is a more specific form of negotiate)
'exclude profit' is the wordplay.
'exclude' becomes 'bar' (synonyms).
'profit' becomes 'gain' (synonyms).
'bar'+'gain'='BARGAIN'
'to' acts as a link.
(Other definitions for bargain that I've seen before include "Deal; item at low price" , "Count on" , "Advantageous purchase" , "Agreement, deal" , "understanding" .)