Salesperson with skill and extremely effusive banter (8)
I believe the answer is:
repartee
'banter' is the definition.
(both can mean jocular conversation)
'salesperson with skill and extremely effusive' is the wordplay.
'salesperson' becomes 'rep' (sales rep).
'with' is a charade indicator (letters next to each other).
'skill' becomes 'art' (both can mean a talent).
'and' means one lot of letters go next to another.
'extremely' means to remove the middle letters (only the extremes of the word are used).
'effusive' with its middle taken out is 'ee'.
'rep'+'art'+'ee'='REPARTEE'
(Other definitions for repartee that I've seen before include "Witty exchanges" , "Series of clever replies" , "Quip" , "Banter - pear tree (anag)" , "Lively exchange" .)