Cashless exchange (6)
I believe the answer is:
barter
'cashless exchange' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for barter that I've seen before include "Trade or swap" , "Trade by exchanging commodities" , "Trade, haggle" , "Trade by direct exchange of goods" , "Exchange goods without using money" .)