Got “piano” clue wrong — showing no regrets? (12)
I believe the answer is:
unapologetic
'showing no regrets?' is the definition.
'got piano clue wrong' is the wordplay.
'wrong' is an anagram indicator.
'got'+'piano'+'clue'='gotpianoclue'
'gotpianoclue' anagrammed gives 'UNAPOLOGETIC'.
(Other definitions for unapologetic that I've seen before include "Impenitent" , "Not expressing regret" , "Not sorry" , "Unrepentant" , "Far from contrite" .)