Collect Charlie carrying Matilda's case (5)
I believe the answer is:
amass
'collect' is the definition.
(I know that collect can be written as amass)
'charlie carrying matilda's case' is the wordplay.
'charlie' becomes 'ass' (both can mean a foolish person).
'carrying' is an insertion indicator.
'case' says to hollow out the word (remove centre letters).
'matilda' with its centre taken out is 'ma'.
'ass' going around 'ma' is 'AMASS'.
(Other definitions for amass that I've seen before include "Accumulate, heap up" , "store" , "Accrue, heap up" , "Be a compiler" , "Put together" .)