Turning mean, tried it on, showing tenacity (13)
I believe the answer is:
determination
'tenacity' is the definition.
(thesaurus)
'turning mean tried it on' is the wordplay.
'turning' indicates an anagram.
'mean'+'tried'+'it'='meantriedit'
'meantriedit' anagrammed gives 'determinati'.
'determinati'+'on'='DETERMINATION'
'showing' is the link.
(Other definitions for determination that I've seen before include "Resolution" , "Resoluteness" , "Firm resolve" , "Firmness of purpose" , "legal decision" .)