Tourist is derived from Tourism. Tourist is related to Hotel. Hotel is a synonym of Pension. 
Traveler is a type of Person. Person does not want (to) Fatigue. Fatigue is similar to Duty. Assignment is a type of Duty. 
Tourism <--DerivedFrom-- Tourist <--RelatedTo--> Hotel <--Synonym--> Pension 
Traveler --IsA--> Person --NotDesires--> Fatigue <--SimilarTo--> Duty <--IsA-- Assignment 