The Englishman's visit is referred to as an unexplained mystery because of his unfamiliarity and baffled looks. Let's explore this answer in detail:

Unfamiliarity:
When the Englishman arrives at the narrator's village, he appears completely unfamiliar with the surroundings. He seems to be out of place and unaware of the customs and traditions of the local people. This unfamiliarity adds to the mystery surrounding his visit.

Baffled Looks:
Throughout his visit, the Englishman constantly wears a look of confusion and bewilderment on his face. He is unable to comprehend the behavior and actions of the villagers. His puzzled expressions further contribute to the unexplained nature of his visit.

Lack of Communication:
The Englishman's inability to communicate effectively with the villagers also adds to the mysterious nature of his visit. Language barriers prevent him from understanding or being understood by the locals. This lack of communication creates an air of mystery and intrigue around his presence.

Strange Behavior:
The Englishman's behavior is also peculiar and unusual. He engages in peculiar activities such as measuring the houses and drawing sketches. These actions appear strange to the villagers, who are unable to comprehend his intentions or purpose. This strange behavior deepens the mystery surrounding his visit.

Contrasting Appearance:
The Englishman's appearance stands out in stark contrast to the villagers. He dresses differently, wears a hat, and carries a walking stick. His attire and accessories are unfamiliar to the locals, further accentuating the sense of mystery and intrigue.

Lack of Explanations:
Lastly, the Englishman does not provide any clear explanations or reasons for his visit. He fails to communicate his intentions or purpose, leaving the villagers puzzled and curious about his presence. This lack of explanation contributes to the unexplained nature of his visit.

In conclusion, the Englishman's visit is referred to as an unexplained mystery due to his unfamiliarity, baffled looks, lack of communication, strange behavior, contrasting appearance, and the absence of clear explanations. All these factors combine to create an air of intrigue and curiosity surrounding his visit, leaving the villagers and the readers in a state of uncertainty.