Nonsense about circle in underground development (4)
I believe the answer is:
root
'underground development' is the definition.
The answer and definition can be both locations as well as being singular nouns.
Perhaps you can see a link between them that I don't see?
'nonsense about circle' is the wordplay.
'nonsense' becomes 'rot' (rot can mean nonsense or rubbish).
'about' is an insertion indicator.
'circle' becomes 'O' (O is a circle).
'rot' enclosing 'o' is 'ROOT'.
'in' acts as a link.
Can you help me to learn more?
(Other definitions for root that I've seen before include "Eg, turnip or carrot" , "Reptile" , "cheer" , "Rummage, origin" , "Part of plant drawing nutrients from soil" .)