This word is in the language, but I like to talk about it anyway (see my first comment). It's composed of two Words:
wandern (to hike, stroll, travel by foot) and
Lust (desire). In its milder form,
Wanderlust indicates a fondness for travelling, especially for travelling abroad; in its stronger form, it implies a real itch or restlessness--people overcome by
Wanderlust do not want to stay home, and when they return from a (possibly extended) trip, immediately start thinking about the next one.