Animal's awfully cute rear (8)
I believe the answer is:
creature
'animal's' is the definition.
(synonyms)
'awfully cute rear' is the wordplay.
'awfully' is an anagram indicator.
'cute'+'rear'='cuterear'
'cuterear' with letters rearranged gives 'CREATURE'.
(Other definitions for creature that I've seen before include "Animal or person" , "Bird, beast, insect etc" , "Bird, beast or fish" , "Living being" , "Animal as distinct from human being" .)