Counterfeit bar of chocolate left out (4)
I believe the answer is:
fake
'counterfeit' is the definition.
(synonyms)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for fake that I've seen before include "Forge" , "Coil of rope" , "Counterfeit object" , "Fraud" , "Very quick" .)