Gloomy study to have a depressing effect (6)
I believe the answer is:
sadden
'a depressing effect' is the definition.
Although both the answer and definition are verbs in their base form, I don't understand how they can define each other.
'gloomy study' is the wordplay.
'gloomy' becomes 'sad' (similar in meaning).
'study' becomes 'den' (den can mean an office or study).
'sad'+'den'='SADDEN'
'to have' is the link.
Can you help me to learn more?
(Other definitions for sadden that I've seen before include "Disappoint" , "Make dejected" , "Make melancholy, depress" , "Cause to feel unhappy" , "Dismay" .)