Conductor expressing Mahler's Sixth well and with dignity (8)
I believe the answer is:
maestoso
'with dignity' is the definition.
(musical term meaning 'in a dignified manner')
'conductor expressing mahler's sixth well' is the wordplay.
'conductor' becomes 'maestro' (I've seen this before).
'expressing' is a deletion indicator.
'mahler's sixth' becomes 'r' (6th letter of 'mahler').
'well' becomes 'so' (I've seen this in other clues).
'maestro' with 'r' taken away is 'maesto'.
'maesto'+'so'='MAESTOSO'
'and' acts as a link.
(Other definitions for maestoso that I've seen before include "Majestically (music)" , "movement" , "scored majestically" , "(In music) with dignity - so-so meat (anag)" , "Majestic" .)