Long tiring walk for vagrant (5)
I believe the answer is:
tramp
This clue is a double definition.
'long tiring walk' is the first definition.
'vagrant' is the second definition.
(thesaurus)
'for' is the link.
(Other definitions for tramp that I've seen before include "Vagrant, hobo" , "Attack with knife" , "Walk heavily, as when weary, or through mud" , "Beggar or vagrant" , "Heavy footsteps" .)