Material for a Scottish banker (5)

I believe the answer is:

tweed

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'material' is the definition.
(I know that tweed is a type of material)

I don't understand the remainder of the clue.

(Other definitions for tweed that I've seen before include "Rough material" , "rough stuff" , "Thick woolen fabric" , "Harris cloth" , "flows across a border" .)

I've seen this clue in The Globe and Mail.

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