Song terrible about middle-age? (5)
I believe the answer is:
dirge
'song' is the definition.
(dirge is a kind of song)
'terrible about middle-age?' is the wordplay.
'terrible' becomes 'dire' (synonyms).
'about' means one lot of letters goes inside another.
'middle' means to look at the middle letters.
The middle of 'age' is 'g'.
'dire' placed around 'g' is 'DIRGE'.
(Other definitions for dirge that I've seen before include "Mournful chant" , "lamentable composition" , "Funereal hymn" , "Lamentation" , "dreary tune" .)