Material from Grobschnitt ultimately old hat (7)
I believe the answer is:
textile
'material' is the definition.
(synonyms)
'grobschnitt ultimately old hat' is the wordplay.
'ultimately' indicates one should take the final letters.
'old' becomes 'ex' (prefix meaning former or onetime).
'hat' becomes 'tile' (old-fashioned term for a hat).
The final letter of 'grobschnitt' is 't'.
't'+'ex'+'tile'='TEXTILE'
'from' acts as a link.
(Other definitions for textile that I've seen before include "The cloth's" , "Cloth, fabric, material" , "Cloth made by weaving or knitting" , "Woven cloth" , "'Fabric, material (7)'" .)