Ear doctor is superior though gloomy (5)
I believe the answer is:
drear
'gloomy' is the definition.
(I know that gloomy can be written as drear)
'ear doctor is superior' is the wordplay.
'doctor' becomes 'Dr' (abbreviation).
'is superior' means one lot of letters go next to another.
'ear' after 'dr' is 'DREAR'.
'though' is the link.
(Other definitions for drear that I've seen before include "Morose" , "Dull and tedious" , "Dull, bleak, depressing" , "Cheerless (literary)" , "grave" .)