sentry (noun)

1. The modern building had a sentry stationed at the entrance, adding a touch of security and elegance to the design.

2. As she walked down the dimly lit street, she couldn't help but feel like a sentry guarding her heart against potential heartbreak.

3. In the novel, the protagonist's father worked as a sentry, always vigilant and watchful for any danger that might approach their home.

4. In the action movie, the sentry patrolled the perimeter of the secret base, keeping an eye out for any suspicious activity.