White House wanting leader gracious and sombre (6)
I believe the answer is:
gloomy
'sombre' is the definition.
(I've seen this before)
'white house wanting leader gracious' is the wordplay.
'white house' becomes 'igloo' (an igloo is made of snow).
'wanting leader' means to remove the first letter.
'gracious' becomes 'my' (both are exclamations of surprise).
'igloo' with its initial letter removed is 'gloo'.
'gloo'+'my'='GLOOMY'
'and' is the link.
(Other definitions for gloomy that I've seen before include "Dark and depressing" , "'Morose, glum (6)'" , "Shadowy" , "Sombre" , "Dreary" .)