Gloomy daughter's back (5)
I believe the answer is:
drear
'gloomy' is the definition.
(I've seen this before)
'daughter's back' is the wordplay.
'daughter' becomes 'd'.
'back' becomes 'rear' (synonyms).
'd'+'rear'='DREAR'
(Other definitions for drear that I've seen before include "Literarily gloomy" , "Dull and tedious" , "Grim" , "Gloomy and cheerless" , "grave" .)