a soldier in a motorized army unit
"The cavalry trooper guided his horse-drawn carriage through the mud, proving that even motorized units had their place before tanks took over."
a mounted police officer
"The trooper pulled his horse to a halt at the edge of the canyon to inspect the vehicle."
a state police officer
"The trooper pulled over my car for speeding on the interstate."
a soldier mounted on horseback
"a cavalryman always takes good care of his mount"
A soldier of private rank in cavalry or armour.
"After hours of intense maneuvering, the weary trooper finally dismounted his horse to tend to a wounded comrade on the battlefield."
To work as a trooper.
"The new recruit was excited to finally start his job as a trooper in the state police force."