Presumably is never out of bounds in unofficial court (8)
I believe the answer is:
kangaroo
'court' is the definition.
(kangaroo court is a kind of court)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for kangaroo that I've seen before include "Would anorak go on the animal?" , "Unofficial court of law" , "Marsupial from down-under" , "Pouched mammal" , "Hopping marsupial" .)