Gloomy daughter is left cuddling mother (6)
I believe the answer is:
dismal
'gloomy' is the definition.
(I know that gloomy can be written as dismal)
'daughter is left cuddling mother' is the wordplay.
'daughter' becomes 'd' (genealogical abbreviation).
'left' becomes 'l' (common abbreviation).
'cuddling' indicates putting letters inside (inserted letters are cuddled or held).
'mother' becomes 'ma' (Ma is another word for mother or mum).
'is'+'l'='isl'
'isl' enclosing 'ma' is 'ismal'.
'd'+'ismal'='DISMAL'
(Other definitions for dismal that I've seen before include "Dull and dreary" , "Depressing in character or appearance" , "dark" , "down in the dumps" , "Feeble" .)