Shown quietly to wander north (6)
I believe the answer is:
proven
'shown' is the definition.
(thesaurus)
'quietly to wander north' is the wordplay.
'quietly' becomes 'p' (p for piano and quiet).
'to wander' becomes 'rove' ('rove' can be a synonym of 'wander').
'north' becomes 'N' (abbreviation).
'p'+'rove'+'n'='PROVEN'
(Other definitions for proven that I've seen before include "Adjective meaning demonstrated beyond doubt" , "Conclusively demonstrated by evidence" , "Established with evidence" , "Established beyond doubt" .)