Animal disheartened, perhaps, when its horn is broken? (5)
I believe the answer is:
rhino
'animal' is the definition.
(short for rhinoceros)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for rhino that I've seen before include "Stumpy" , "Thick-skinned beast" , "Large horned mammal" , "Horned beast (abbr.)" , "Moola" .)