Passing here, MP befuddled with ale (9)
I believe the answer is:
ephemeral
'passing' is the definition.
(synonyms)
'here mp befuddled with ale' is the wordplay.
'befuddled with' is an anagram indicator.
'here'+'mp'='heremp'
'heremp' anagrammed with 'ale' makes 'EPHEMERAL'.
(Other definitions for ephemeral that I've seen before include "staying for a little while" , "Lasting only briefly" , "Transitory" , "not going to last long" , "life's too short" .)