Shut up and employ Charlie for good! (6)
I believe the answer is:
encage
'shut up' is the definition.
(thesaurus)
'and employ charlie for good' is the wordplay.
I cannot quite understand how this works, but
'and' could be 'n' (common abbreviation for 'and') and 'n' is located in the answer.
'charlie' could be 'c' (phonetic alphabet: alpha, bravo, charlie etc.) and 'c' is found in the answer.
'good' could be 'g' (abbreviation) and 'g' is located in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for encage that I've seen before include "Pen" , "Bang up" , "Put behind bars" .)