The beast can show zeal in setting a broken leg! (7)
I believe the answer is:
gazelle
'the beast' is the definition.
(I have seen 'Graceful beast' mean 'gazelle' so perhaps 'beast' could also mean 'gazelle')
'show zeal in setting a broken leg' is the wordplay.
I cannot really understand how this works, but
an anagram of 'zeal' is 'azel' which is within the answer.
an anagram of 'leg' is 'gle' which is within the left over letters.
This accounts for all the letters.
This may be the basis of clue (or it may be nonsense).
'can' is the link.
Can you help me to learn more?
(Other definitions for gazelle that I've seen before include "Thomson's antelope" , "Slender antelope" , "Small graceful antelope" , "Large-eyed antelope" , "''both / beautiful, one a ...'' (Yeats)" .)