Copper left -- trial date coming up, getting close (3-2-3)
I believe the answer is:
cul-de-sac
'close' is the definition.
(thesaurus)
'copper left trial date coming up' is the wordplay.
'copper' becomes 'cu' (chemical symbol).
'left' shows that the letters should be reversed in order.
'trial' becomes 'case' (I've seen this in other clues).
'date coming up' becomes 'dl' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'case'+'dl'='casedl'
'casedl' reversed gives 'ldesac'.
'cu'+'ldesac'='CUL-DE-SAC'
'getting' is the link.
Can you help me to learn more?
(Other definitions for cul-de-sac that I've seen before include "Street with only one exit-entrance" , "Street closed at one end" , "Dead-end street" , "'There's only one way in and out (3,2,3)'" , "Blind alley" .)