When it comes to a toilet, former leader is snooty (5)
I believe the answer is:
aloof
'snooty' is the definition.
(I've seen this in another clue)
'when it comes to a toilet former leader' is the wordplay.
'when it comes to' becomes 'a' (I can't explain this - if you can you should believe this answer much more).
'a toilet' becomes 'loo' (loo can informally mean a toilet).
'leader' indicates taking the first letters.
The first letter of 'former' is 'f'.
'a'+'loo'+'f'='ALOOF'
'is' acts as a link.
Can you help me to learn more?
(Other definitions for aloof that I've seen before include "Coldly distant" , "Detached, distant" , "Indifferent - by oneself" , "apart from all else" , "Displaying supercilious reserve" .)