Flap cut back in marsupial (6)
I believe the answer is:
wombat
'marsupial' is the definition.
(I know that wombat is a type of marsupial)
'flap cut back' is the wordplay.
'flap' becomes 'tab' (both can mean a small piece of material).
'cut' becomes 'mow' (as in mowing a lawn).
'back' shows that the letters should be reversed in order.
'tab'+'mow'='tabmow'
'tabmow' reversed gives 'WOMBAT'.
'in' is the link.
(Other definitions for wombat that I've seen before include "Marsupial of Oz" , "Burrowing animal" , "Australian animal resembling small bear" , "Australian animal like small bear" , "Australian burrowing marsupial" .)