Tovarishch

Tovarishch was a Russian word meaning comrade, friend, or ally. After possessing Captain Sorin, Fenric called Ace tovarishch to trick her into revealing how to beat the Seventh Doctor's chess puzzle. (TV: The Curse of Fenric)

Felnikov later called Ace tovarishch when they met again in 1989, after first meeting in 1967. (AUDIO: Crime of the Century)