Big road twice has carbon copy (5)
I believe the answer is:
mimic
'copy' is the definition.
(I know that mimic is a more specific form of the action copy)
'big road twice has carbon' is the wordplay.
'big road' becomes 'mi' (resembles M1 motorway. I am not sure about the 'big' bit.).
'twice' says to double the letters.
'has' says to put letters next to each other.
'carbon' becomes 'C' (chemical symbol).
'mi' doubled is 'mimi'.
'mimi'+'c'='MIMIC'
Can you help me to learn more?
(Other definitions for mimic that I've seen before include "Ape" , "Skilled imitator" , "Imitate, especially for satirical effect" , "Copy (voice, mannerisms)" , "Imitate for humorous reasons" .)