Argument about vessel's treasure (7)
I believe the answer is:
worship
'treasure' is the definition.
(thesaurus)
'argument about vessel's' is the wordplay.
'argument' becomes 'row' (I've seen this before).
'about' shows that the letters should be reversed in order.
'vessel' becomes 'ship' (ship is a kind of vessel**).
'row' reversed gives 'wor'.
'wor'+'ship'='WORSHIP'
(Other definitions for worship that I've seen before include "Adoration of a divine being" , "Honour" , "Revere" , "what can priest offer?" , "Offer praise to" .)