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