Charlie, with hint of anger, ridicules collusion (7)
I believe the answer is:
cahoots
'collusion' is the definition.
(to be 'in cahoots' is to collude with someone)
'charlie with hint of anger ridicules' is the wordplay.
'charlie' becomes 'C' (phonetic alphabet: alpha, bravo, charlie etc.).
'with' says to put letters next to each other.
'hint of' suggests taking the first letters (the smallest possible amount of the word).
'ridicules' becomes 'hoots' (I can't explain this - if you can you should believe this answer much more).
The initial letter of 'anger' is 'a'.
'c'+'a'+'hoots'='CAHOOTS'
Can you help me to learn more?
(Other definitions for cahoots that I've seen before include "(In) conspiracy" , "League" , "In - means colluding" , "Collusion" , "In such agreement" .)