South African defence is gloomy (3)
I believe the answer is:
sad
'gloomy' is the definition.
(similar in meaning)
'south african defence' is the wordplay.
'south' becomes 's' (abbreviation).
'african defence' becomes 'ad' (this could be a standard abbreviation of which I'm unaware).
's'+'ad'='SAD'
'is' is the link.
Can you help me to learn more?
(Other definitions for sad that I've seen before include "Melancholy, triste" , "Melancholy, downhearted" , "Sorrowful, unhappy" , "Deplorable" , "Blue" .)