Kangaroo or koala (6)
I believe the answer is:
animal
I believe this is a double definition.
'kangaroo' is the first definition.
(thesaurus)
'koala' is the second definition.
(thesaurus)
(Other definitions for animal that I've seen before include "One sharing our kingdom" , "Uncivilised person" , "I''m Alan (anag) - a wild, crazy person" , "something in the zoo?" , "It shares the world with vegetable and mineral" .)