say it: TROO-pur
trooper is a noun meaning "a soldier in a motorized army unit". It carries 4 recorded senses.
a soldier in a motorized army unit
a mounted police officer
a state police officer
a soldier mounted on horseback
“a cavalryman always takes good care of his mount”
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for trooper come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.