guard; security guard; doorkeeper
Refers to a person stationed at an entrance or facility to provide security, control access, or perform caretaking duties. Often used for guards at buildings, schools, or companies.
A guard is standing in front of the gate.
Please show your ID to the guard.
When I entered the company, the guard stopped me and asked my name.
At night, the guard patrols inside the building.
He has served as the university's guard for many years.