Grew old in the attempt - a calamity (7)
I believe the answer is:
tragedy
'a calamity' is the definition.
(I know that calamity can be written as tragedy)
'grew old in the attempt' is the wordplay.
'grew old' becomes 'aged' ('age' can be a synonym of 'grow old').
'in' indicates putting letters inside.
'the attempt' becomes 'try' ('try' can be a synonym of 'attempt').
'aged' going into 'try' is 'TRAGEDY'.
(Other definitions for tragedy that I've seen before include "story ending unhappily" , "Serious catastrophe" , "Gyrated (anag)" , "play like 'Macbeth', for example" , "Play ending unhappily" .)