Producing nothing again in farm building (6)
I believe the answer is:
barren
'producing nothing' is the definition.
I can't judge whether this defines the answer.
'again in farm building' is the wordplay.
'again' becomes 're' (prefix meaning 'again').
'in' means one lot of letters goes inside another.
'farm building' becomes 'barn' (barn is a kind of farm building).
're' inserted into 'barn' is 'BARREN'.
Can you help me to learn more?
(Other definitions for barren that I've seen before include "Arid of unfertile" , "Not fertile, unproductive" , "Unable to bear fruit, not fertile" , "Bare and bleak" , "Bleak, lifeless" .)