Material taken to court by egghead (5)
I believe the answer is:
suede
'material' is the definition.
(I know that suede is a type of material)
'taken to court by egghead' is the wordplay.
'taken to court' becomes 'sued' (to sue someone is to take them to court).
'by' means one lot of letters go next to another.
'egghead' becomes 'e' (head letter of 'egg').
'sued'+'e'='SUEDE'
(Other definitions for suede that I've seen before include "Soft goatskin" , "Fabric" , "Soft leather with one side napped" , "Type of leather" , "Undressed leather" .)