Ridiculous orange beast (6)
I believe the answer is:
onager
'beast' is the definition.
(equine species native to Asia)
'ridiculous orange' is the wordplay.
'ridiculous' is an anagram indicator.
'orange' with letters rearranged gives 'ONAGER'.
(Other definitions for onager that I've seen before include "Creature" , "Strangely, the wild ass might be orange" , "Asian wild ass - orange (anag)" , "Orange Asiatic ass" , "donkey" .)