trooper

nouns

a soldier in a motorized army unit
cavalryman, trooper
a mounted policeman
trooper
is a type of (narrower)
a member of a police force
"it was an accident, officer"
officer, police officer, policeman
a state police officer
state trooper, trooper
a soldier mounted on horseback
"a cavalryman always takes good care of his mount"
cavalryman, trooper