com·bat·ant 
/kəmˈbætn̩t, Brit ˈkɒmbətənt/ noun
plural com·bat·ants /kəmˈbætn̩t, Brit ˈkɒmbətənt/ noun [count] : a person, group, or country that fights in a war or battle
▪ Britain was a main/major combatant in World War II. — often used before another noun ▪ combatant ships/nations
▪ Britain was a main/major combatant in World War II. — often used before another noun ▪ combatant ships/nations
