noun
Refers to a person assigned to keep watch, often in a security or surveillance context. The term is straightforward but not extremely common in everyday conversation.
工事現場に看視人が立っていた。
A lookout was standing at the construction site.
看視人が不審者を見つけて通報した。
The guard spotted a suspicious person and reported it.
見張り is a more everyday word for a lookout or watchman, whereas 看視人 sounds more formal or technical.
Compound of 看 (watch, observe), 視 (look, inspect), and 人 (person). The exact historical derivation is uncertain, but the spelling is conventionally associated with the meaning of a person who keeps watch.