Frenchman in part upset by hike (5)
I believe the answer is:
tramp
'hike' is the definition.
(I've seen this before)
'frenchman in part upset' is the wordplay.
'frenchman' becomes 'm' (abbreviation for Monsieur - like 'Mr').
'upset' indicates anagramming the letters.
'm'+'part'='mpart'
'mpart' is an anagram of 'TRAMP'.
'by' acts as a link.
(Other definitions for tramp that I've seen before include "Trudge; vagrant" , "Vagrant - cargo ship" , "Walk heavily like hobo" , "Vagrant, long walk" , "I usually walk" .)