country bumpkin visiting the city; out-of-towner; yokel
A mildly mocking or affectionate term used by city dwellers for someone from the countryside who is visiting the big city and may seem unsophisticated or overly excited. Often used in a teasing, lighthearted way rather than as a harsh insult.
The out-of-towner who came to Tokyo was confused about how to take the train.
He hated being treated like a country bumpkin, so he desperately learned the geography of Tokyo.