Magnificent piano left on purpose in here with front missing (11)
I believe the answer is:
resplendent
'magnificent' is the definition.
(synonyms)
'piano left on purpose in here with front missing' is the wordplay.
I cannot really understand how this works, but
'piano' could be 'p' (musical abbreviation) and 'p' is located in the answer.
'left' could be 'l' (common abbreviation) and 'l' is found in the answer.
'on' could be 're' ('on' can be mean 'with reference to') and 're' is present in the answer.
'purpose' could be 'end' (both can mean a goal) and 'end' is present in the answer.
'here' could be 'ent' (I've seen this in other clues) and 'ent' is present in the answer.
A single letter 's' remains which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
(Other definitions for resplendent that I've seen before include "Gloriously beautiful" , "Sumptuously impressive" , "Shining, brilliant" , "Dazzling" , "Colourfully sumptuous" .)