Possibly piles of sales talk (5)
I believe the answer is:
spiel
'sales talk' is the definition.
(I've seen this in another clue)
'possibly piles' is the wordplay.
'possibly' indicates anagramming the letters.
'piles' anagrammed gives 'SPIEL'.
'of' is the link.
(Other definitions for spiel that I've seen before include "Salesman's glib patter" , "Piles (anag.)" , "Salesperson's speech" , "Sales pitch" , "Glib style of talk associated with salesmen" .)