The Yard is after gangster from Kildare for name of mule (6)
I believe the answer is:
donkey
'mule' is the definition.
(thesaurus)
'the yard is after gangster from kildare for name' is the wordplay.
I cannot quite understand how this works, but
'yard' could be 'k' (synonyms) and 'k' is present in the answer.
'from' could be 'o' (I've seen this in other clues) and 'o' is located in the answer.
'name' could be 'n' (common abbreviation e.g. on forms) and 'n' is found in the answer.
The remaining letters 'dey' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
'of' acts as a link.
Can you help me to learn more?
(Other definitions for donkey that I've seen before include "Mary's transport" , "Braying animal" , "Domesticated ass" , "Domesticated animal" , "Beasts of burden" .)