Confusion as Charles invests zero (5)
I believe the answer is:
chaos
'confusion' is the definition.
(I know that chaos is a type of confusion)
'charles invests zero' is the wordplay.
'charles' becomes 'Chas' (shortened form).
'invests' is an insertion indicator (inserted letters are invested).
'zero' becomes 'O' (O resembles 0).
'chas' enclosing 'o' is 'CHAOS'.
'as' acts as a link.
(Other definitions for chaos that I've seen before include "State of extreme confusion and disorder" , "Utter confusion" , "Pandemonium" , "Bedlam" , "disarray" .)