Spurn salesman with line in profit (7)
I believe the answer is:
repulse
'spurn' is the definition.
(thesaurus)
'salesman with line in profit' is the wordplay.
'salesman' becomes 'rep' (I've seen this before).
'with' means one lot of letters go next to another.
'line' becomes 'l'.
'in' means one lot of letters goes inside another.
'profit' becomes 'use' (I've seen this before).
'l' put into 'use' is 'ulse'.
'rep'+'ulse'='REPULSE'
(Other definitions for repulse that I've seen before include "Rebuff, drive back" , "Ward off" , "Cause to feel intense aversion" , "Beat back" , "Drive back or reject" .)