Australian with organ failure stops climbing tree (8)
I believe the answer is:
kangaroo
'australian' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
'organ failure stops climbing tree' is the wordplay.
'failure' indicates an anagram.
'stops' indicates putting letters inside (stopping can mean blocking a gap).
'climbing' says the letters should be written in reverse (in a down clue, letters climb up).
'tree' becomes 'oak' (oak is a type of tree).
'oak' back-to-front is 'kao'.
'organ' anagrammed gives 'ngaro'.
'ngaro' put into 'kao' is 'KANGAROO'.
'with' is the link.
Can you help me to learn more?
(Other definitions for kangaroo that I've seen before include "one jumps" , "Marsupial that boxes" , "Hopping marsupial" , "impromptu kind of court" , "Bounding marsupial" .)