Call Charlie and ridicule the cot (4)
I believe the answer is:
crib
'the cot' is the definition.
('crib' can be a synonym of 'cot')
'call charlie and ridicule' is the wordplay.
I cannot really see how this works, but
'charlie' could be 'c' (phonetic alphabet: alpha, bravo, charlie etc.) and 'c' is located in the answer.
'ridicule' could be 'rib' (synonyms) and 'rib' is found in the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for crib that I've seen before include "Cradle; translation" , "24 ac" , "Cot; translation cheat" , "Card game for two" , "Pirate" .)