Let off a gun at the animal (3)
I believe the answer is:
gnu
'animal' is the definition.
(type of antelope)
'let off a gun at' is the wordplay.
'gun' anagrams to 'GNU'.
Though, I'm not sure how the anagram is indicated.
'the' is the link.
Can you help me to learn more?
(Other definitions for gnu that I've seen before include "Literally wild beast" , "Strange gun for an antelope" , "Wildebeest" , "Large heavy antelope" , "Gun for a kind of deer" .)