Australian native agreeable about accepting a transplanted organ (8)
I believe the answer is:
kangaroo
'australian native' is the definition.
Although both the answer and definition are singular nouns, I can't understand how they can define each other.
'agreeable about accepting a transplanted organ' is the wordplay.
'agreeable' becomes 'oak' (I am not sure about this - if you are sure you should believe this answer much more).
'about' is a reversal indicator.
'accepting' indicates putting letters inside.
'a transplanted' indicates anagramming the letters.
'oak' back-to-front is 'kao'.
'organ' anagrammed gives 'ngaro'.
'kao' enclosing 'ngaro' is 'KANGAROO'.
Can you help me to learn more?
(Other definitions for kangaroo that I've seen before include "Large Australian marsupial" , "Australian animal -- a no-go ark (anag)" , "Aussie boxer" , "impromptu kind of court" , "Marsupial from down-under" .)