Attempt to conceal old misfortune (7)
I believe the answer is:
tragedy
'misfortune' is the definition.
(I know that tragedy is a type of misfortune)
'attempt to conceal old' is the wordplay.
'attempt to' becomes 'try' (I've seen this in other clues).
'conceal' indicates putting letters inside.
'old' becomes 'aged' (similar in meaning).
'try' enclosing 'aged' is 'TRAGEDY'.
(Other definitions for tragedy that I've seen before include "Drama genre" , "event causing great pain" , "Serious type of play" , "play such as Othello" , "Play ending unhappily" .)