Put down iron again (7)
I believe the answer is:
repress
'put down' is the definition.
(I've seen this before)
'iron again' is the wordplay.
I cannot really understand how this works, but
'iron' could be 'press' (I've seen this before) and 'press' is present in the answer.
'again' could be 're' (prefix meaning 'again') and 're' is present in the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for repress that I've seen before include "Put in irons, maybe" , "keep back" , "Subdue" , "bottle up" , "Curb" .)