Forked out to obtain large tartan cloth (5)
I believe the answer is:
plaid
'tartan cloth' is the definition.
(I've seen this before)
'forked out to obtain large' is the wordplay.
'forked out' becomes 'paid' (I've seen this before).
'to obtain' means one lot of letters goes inside another.
'large' becomes 'l'.
'paid' enclosing 'l' is 'PLAID'.
(Other definitions for plaid that I've seen before include "Cloth with a criss-cross design" , "piece of cloth" , "Tartan cloth, part of Highland dress" , "Part of Scots dress or Welsh party" , "Tartan-pattern cloth" .)