Left, for instance, to finish traditional tale (6)
I believe the answer is:
legend
'traditional tale' is the definition.
'left for instance to finish' is the wordplay.
'left' becomes 'l' (common abbreviation).
'for instance' becomes 'eg' ('e.g.' can be a synonym of 'for instance').
'to finish' becomes 'end' ('end' can be a synonym of 'finish').
'l'+'eg'+'end'='LEGEND'
(Other definitions for legend that I've seen before include "Story shows the opposite" , "Story about mytical beings" , "famous player?" , "Traditional story - inscription" , "Stanley Matthews, perhaps" .)