Vagrant worker was harassed by FBI agent (7)
I believe the answer is:
swagman
'vagrant' is the definition.
(thesaurus)
'was harassed by fbi agent' is the wordplay.
'harassed' indicates an anagram.
'by' is a charade indicator (letters next to each other).
'fbi agent' becomes 'gman' ('G-man' can be a synonym of 'fbi agent').
'was' anagrammed gives 'swa'.
'swa'+'gman'='SWAGMAN'
'worker' is the link.
I am not very happy about this link. It may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for swagman that I've seen before include "Australian tramp" , "itinerary" , "Aussie worker" , "Drifter" .)