Depression etched into a smiling face? (6)
I believe the answer is:
dimple
'depression' is the definition.
(I know that dimple is a type of depression)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for dimple that I've seen before include "Small depression in flesh" , "Limped (anag.)" , "Shallow depression" , "Small hollow in cheek or chin" , "Fleshy dent" .)