Follow the man leaving the bar (5)
I believe the answer is:
trail
'follow' is the definition.
(thesaurus)
'the man leaving the bar' is the wordplay.
'man' becomes 'he'.
'leaving' indicates named letters should be taken away.
'the bar' becomes 'rail' (rail is a kind of bar).
'the' with 'he' taken out is 't'.
't'+'rail'='TRAIL'
(Other definitions for trail that I've seen before include "Drop behind" , "Track or mark left by something that has passed" , "Drag along the ground" , "Linger behind" , "Follow - track" .)