Time to complain in shadow (5)
I believe the answer is:
trail
'shadow' is the definition.
(trailing is a kind of shadowing)
'time to complain' is the wordplay.
'time' becomes 't' (abbreviation).
'to complain' becomes 'rail' (railing is a kind of complaining).
't'+'rail'='TRAIL'
'in' acts as a link.
(Other definitions for trail that I've seen before include "Beaten path; follow" , "Linger behind" , "Dog - track" , "Stalk" , "Beaten path; track" .)