Form bookmaker used upset old tax company (6)
I believe the answer is:
octavo
'form bookmaker' is the definition.
The definition and answer can be both human attributes as well as being singular nouns.
Perhaps you can see a link between them that I can't see?
'upset old tax company' is the wordplay.
'upset' is a reversal indicator.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'tax' becomes 'vat' (UK Value Added Tax).
'company' becomes 'co' (abbreviation).
'o'+'vat'+'co'='ovatco'
'ovatco' written backwards gives 'OCTAVO'.
'used' acts as a link.
Can you help me to learn more?
(Other definitions for octavo that I've seen before include "Size of a book, pages are made by folding a sheet of paper three times to form eight leaves (6)" , "An eight-leaved book or page" , "Size of book page" , "Common book size" .)