Hearing related Australian was no saint (5)
I believe the answer is:
aural
'hearing' is the definition.
(thesaurus)
'related australian was no saint' is the wordplay.
I cannot quite see how this works, but
'australian' could be 'au' and 'au' is located in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for aural that I've seen before include "To do with an ear or hearing" , "To do with hearing or the ears" , "Received by the ears" , "Relating to sense of hearing" , "Relating to the hearing organs" .)