Passing me her pale pants (9)
I believe the answer is:
ephemeral
'passing' is the definition.
('ephemeral' can be a synonym of 'passing')
'me her pale pants' is the wordplay.
'pants' is an anagram indicator (UK informal term for 'nonsense' or 'rubbish').
'me'+'her'+'pale'='meherpale'
'meherpale' anagrammed gives 'EPHEMERAL'.
(Other definitions for ephemeral that I've seen before include "A mere help (anag) - short-lived" , "life's too short" , "Having only brief existence" , "Short lived" , "Lasting only briefly" .)