trooperPronunciation: /ˈtruːpə/Translate trooper | into French | into Italian | into Spanish Definition of trooper noun 1a private soldier in a cavalry or armoured unit. a cavalry horse. chiefly British a troopship. 2chiefly US a mounted police officer. US a state police officer. Phrases swear like a trooper swear a great deal: his fists were clenched and he was swearing like a troopertrooper in other Oxford dictionaries Definition of trooper in the US English dictionary