Urine's a little vile (7)
I believe the answer is:
noisome
'vile' is the definition.
(synonyms)
'urine's a little' is the wordplay.
'urine' becomes 'noi' (I can't justify this - if you can you should give a lot more credence to this answer).
'a little' becomes 'some' (I've seen this before).
'noi'+'some'='NOISOME'
Can you help me to learn more?
(Other definitions for noisome that I've seen before include "noxious smells" , "Foul-smelling, noxious" , "Offensively smelling" , "Evil-smelling - sounds loud" , "Smelling badly" .)