Slavers exchanged or sold (6)
I believe the answer is:
drools
'slavers' is the definition.
('drool' can be a synonym of 'slaver')
'exchanged or sold' is the wordplay.
'exchanged' is an anagram indicator.
'or'+'sold'='orsold'
'orsold' with letters rearranged gives 'DROOLS'.
(Other definitions for drools that I've seen before include "Gushes" , "Slavers" , "Salivates" , "Waters at the mouth" .)