trooper
UK: ˈtruːpə | US: ˈtruːpər
n. 1. A soldier in a cavalry or armored unit.
n. 2. A state police officer (chiefly US).
n. 3. A reliable or resilient person (informal, e.g., "She's a real trooper").
The word trooper emerged in the 17th century, derived from troop (a unit of soldiers) + -er. It originally referred to cavalry soldiers, reflecting the organizational structure of early modern armies. Over time, it expanded to include state police officers (US) and colloquially to describe someone enduring hardship steadfastly—metaphorically likening resilience to a soldier's fortitude.
The trooper patrolled the highway during the storm.
He served as a cavalry trooper in the 19th century.
Despite her injury, she finished the race—what a trooper!
State troopers were deployed to control the protest.
The veteran was proud of his years as an armored trooper.