Thief

A thief was an individual who took property which did not belong to them, often as "profession," meaning they survived primarily by stealing. The Doctor encountered a wide variety of individuals in his travels, including thieves.

The First Doctor, Barbara, Ian, and Susan met Robin Hood, Little John, and Will Scarlet. The three were members of a group of outlaws who stole from both the rich and poor as a source of income. (PROSE: The Thief of Sherwood)

While in Napoleonic Russia, the First Doctor, Steven, and Dodo encountered a shapeshifter they called the Shape Thief. The Shape Thief changed into the Doctor and tried to steal the TARDIS. (AUDIO: Mother Russia)

The Third Doctor incorporated an anti-thief device into Bessie. The Doctor used the device at least once to aid in the recovery of the Recovery 7 landing capsule which had been stolen by two thieves. (TV: The Ambassadors of Death)

Liz Shaw, when working at the University of Rome on a bust of Nero with a man named Jonas Smythe (the Fifth Doctor), encountered a thief who tried to steal the bust. (PROSE: Flashpoint)

When he tried to visit his friends Lord and Lady Tubbs, the Tenth Doctor discovered a thief had tried to steal an ancient horologe, dropped it, and transported those in the immediate vicinity into a different kind of time. (COMIC: 13 O'Clock)