Charles throttling Oscar in disorder (5)
I believe the answer is:
chaos
'disorder' is the definition.
(chaos is a kind of disorder)
'charles throttling oscar' is the wordplay.
'charles' becomes 'Chas' (shortened form).
'throttling' indicates putting letters inside.
'oscar' becomes 'O' (phonetic alphabet: alpha, bravo, charlie etc.).
'chas' enclosing 'o' is 'CHAOS'.
'in' is the link.
(Other definitions for chaos that I've seen before include "Absence of order" , "Complete disorder and confusion" , "Anarchy" , "A total shambles" , "[MAYHEM]" .)