Do they confess to a proprietorial interest? (6)
I believe the answer is:
owners
'do they' is the definition.
The definition suggests a plural noun which matches the answer.
'confess to a proprietorial interest?' is the wordplay.
'confess' becomes 'own' (I've seen this before).
'to a proprietorial interest?' becomes 'ers' (I am not sure about this - if you are sure you should believe this answer much more).
'own'+'ers'='OWNERS'
Can you help me to learn more?
(Other definitions for owners that I've seen before include "Those in lawful possession, as of house" , "Holders, possessors" , "Worsen for possessors" , "Legal possessors" , "Proprietors" .)