A person assigned to watch over a place, activity, or people for safety, security, or supervision. Common in contexts like swimming pools, construction sites, and surveillance.
The pool lifeguard is always watching over the children.
A watchman is stationed at the construction site.
pharmaceutical inspector
parking inspector; parking enforcement officer; traffic warden
food sanitation inspector
Compound of 監視 (kanshi, 'monitoring') + 員 (in, 'member' or 'personnel'), literally 'monitoring person'.