Share deals? Errs badly in practice (5,9)
I believe the answer is:
dress rehearsal
'practice' is the definition.
(dress rehearsal is a kind of practice)
'share deals? errs badly' is the wordplay.
'badly' is an anagram indicator.
'share'+'deals'+'errs'='sharedealserrs'
'sharedealserrs' anagrammed gives 'DRESS REHEARSAL'.
'in' is the link.
(Other definitions for dress rehearsal that I've seen before include "Strip show doesn't need such" , "trial run" , "last chance to get things right" , "Final play run-through" , "last practice" .)