Confuse double folio in bundle (6)
I believe the answer is:
baffle
'confuse' is the definition.
(I know this)
'double folio in bundle' is the wordplay.
'double' says to double the letters.
'folio' becomes 'f' (abbreviation listed in Chambers).
'in' indicates putting letters inside.
'bundle' becomes 'bale' (bale is a kind of bundle).
'f' doubled is 'ff'.
'ff' placed inside 'bale' is 'BAFFLE'.
(Other definitions for baffle that I've seen before include "Perplex and bewilder" , "Bemuse" , "Puzzle and perplex" , "Mystify, bewilder" , "Mystify, flummox" .)