Soon rule Charlie out (4)
I believe the answer is:
anon
'soon' is the definition.
(I've seen this before)
'rule charlie out' is the wordplay.
'rule' becomes 'canon' (canon is a kind of rule).
'charlie' becomes 'c' (phonetic alphabet: alpha, bravo, charlie etc.).
'out' suggests deleting specific letters.
'canon' with 'c' removed is 'ANON'.
(Other definitions for anon that I've seen before include "Presently - or unknown" , "Immediately" , "Writer unknown" , "At another time and with no identity, in short" , "Some time soon" .)