Chilean linesman in underground area (6)
I believe the answer is:
neruda
'chilean linesman' is the definition.
(poet Pablo Neruda - a man who wrote lines)
'underground area' is the wordplay.
I cannot really understand how this works, but
'area' could be 'ne' and 'ne' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
'in' is the link.
(Other definitions for neruda that I've seen before include "Pablo --, Chilean poet and politician" , "S American poet" .)