Follow the first to complain (5)
I believe the answer is:
trail
'follow' is the definition.
(trail can mean to follow in secret)
'first to complain' is the wordplay.
'first to' becomes 't' (1st letter of 'to').
'complain' becomes 'rail' (railing is a kind of complaining).
't'+'rail'='TRAIL'
'the' is the link.
(Other definitions for trail that I've seen before include "Need to catch up with" , "Beaten path; lag" , "Pursue" , "Forest path" , "Straggle" .)