Make material corroded (9)
I believe the answer is:
fabricate
'make' is the definition.
(I know this)
'material corroded' is the wordplay.
'material' becomes 'fabric' (synonyms).
'corroded' becomes 'ate' ('eat' can be a synonym of 'corrode').
'fabric'+'ate'='FABRICATE'
(Other definitions for fabricate that I've seen before include "Tell lies" , "Make up; manufacture" , "Construct or invent" , "Invent, make up" , "forge" .)